xANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

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oTRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

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Commission file number 001-37558

Nabriva Therapeutics AG

(Exact name of registrant as specified in its charter)

Republic of Austria

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(I.R.S. Employer Identification No.)

Leberstrasse 20

1110 Vienna, Austria

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(Address of principal executive offices)

(Zip Code)

43 (0)1 740 930

(Registrants telephone number, including area code)

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As of June 30, 2016 (the last business day of the registrants most recently completed second fiscal quarter), the aggregate market value of the registrants voting securities held by non-affiliates was approximately $74.7 million based on the last reported sale price of the registrants ADSs on June 30, 2016. As of March 1, 2017, the registrant had 2,719,851 common shares outstanding, of which 2,259,208 are represented by 22,592,080 ADS.

·the timing and conduct of our clinical trials of our lead product candidate, lefamulin, including statements regarding the timing and completion of the trials, and the period during which the results of the trials will become available;

·other risks and uncertainties, including those described in the Risk Factors section of this Form 10-K.

We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included in this Annual Report, particularly in the Risk Factors section of this Annual Report, that we believe could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make.

You should read this Annual Report and the documents that we have filed as exhibits to this Annual Report completely and with the understanding that our actual future results may be materially different from what we expect. We do not assume any obligation to update any forward-looking statements, except as required by applicable law.

This Annual Report includes statistical and other industry and market data that we obtained from industry publications and research, surveys and studies conducted by third parties. Industry publications and third-party research, surveys and studies generally indicate that their information has been obtained from sources believed to be reliable, although they do not guarantee the accuracy or completeness of such information.

We are a clinical stage biopharmaceutical company engaged in the research and development of novel anti-infective agents to treat serious infections, with a focus on the pleuromutilin class of antibiotics. We are developing our lead product candidate, lefamulin, to be the first pleuromutilin antibiotic available for systemic administration in humans. We are developing both intravenous, or IV, and oral formulations of lefamulin for the treatment of community-acquired bacterial pneumonia, or CABP and intend to develop lefamulin for additional indications other than pneumonia. We have completed a Phase 2 clinical trial of lefamulin for acute bacterial skin and skin structure infections, or ABSSSI. Based on the clinical results of lefamulin for ABSSSI, as well as its rapid tissue distribution, including substantial penetration into lung fluids and lung immune cells, we have initiated two pivotal, international Phase 3 clinical trials of lefamulin for the treatment of moderate to severe CABP.

We initiated the first of our Phase 3 trials, which we refer to as LEAP 1, in September 2015 and initiated the second trial, which we refer to as LEAP 2, in April 2016. These are the first clinical trials we have conducted with lefamulin for the treatment of CABP. Both trials are designed to follow draft guidance published by the FDA for the development of drugs for CABP and guidance from the European Medicines Agency, or EMA, for the development of antibacterial agents. Based on our estimates regarding patient enrollment, we expect to have top-line data from LEAP 1 in the third quarter of 2017. With respect to LEAP 2, based on current projections, we expect to complete patient enrollment in the fourth quarter of 2017, and we anticipate receiving top-line data for LEAP 2 in the first quarter of 2018. If the results of these trials are favorable, including achievement of the primary efficacy endpoints of the trials, we expect to submit applications for marketing approval for lefamulin for the treatment of CABP in both the United States and Europe in 2018. We believe that lefamulin is well suited for use as a first-line empiric monotherapy for the treatment of CABP because of its novel mechanism of action, spectrum of activity, including against multi-drug resistant pathogens, achievement of substantial drug concentrations in lung fluids and lung immune cells, availability as both an IV and oral formulation and favorable safety and tolerability profile.

The U.S. Food and Drug Administration, or FDA, has designated each of the IV and oral formulations of lefamulin as a qualified infectious disease product, or QIDP, which provides for the extension of statutory exclusivity periods in the United States for an additional five years upon FDA approval of the product for the treatment of CABP and granted fast track designation to these formulations of lefamulin. Fast track designation is granted by the FDA to facilitate the development and expedite the review of drugs that treat serious conditions and fill an unmet medical need. The fast track designation for the IV and oral formulations of lefamulin will allow for more frequent interactions with the FDA, the opportunity for a rolling review of any new drug application, or NDA, we submit and eligibility for priority review and a shortening of the FDAs goal for taking action on a marketing application from ten months to six months.

We believe that pleuromutilin antibiotics can help address the major public health threat posed by bacterial resistance, which the World Health Organization, or WHO, characterized in 2010 as one of the three greatest threats to human health. Increasing resistance to antibiotics used to treat CABP is a growing concern and has become an issue in selecting the appropriate initial antibiotic treatment prior to determining the specific microbiological cause of the infection, referred to as empiric treatment. For example, the U.S. Centers for Disease Control and Prevention, or CDC, has classified Streptococcus pneumoniae, the most common respiratory pathogen, as a serious threat to human health as a result of increasing resistance to currently available antibiotics. In addition, the CDC recently reported on the growing evidence of widespread resistance to macrolides, widely used antibiotics that disrupt bacterial protein synthesis, in Mycoplasma pneumoniae, a common cause of CABP that is associated with significant morbidity and mortality. Furthermore, Staphylococcus aureus, including methicillin-resistant S. aureus, or MRSA, which has also been designated as a serious threat to human health by the CDC, has emerged as a more common cause of CABP in some regions of the world, and a possible pathogen to be covered with empiric therapy.

In recognition of the growing need for the development of new antibiotics, recent regulatory changes, including priority review and regulatory guidance enabling smaller clinical trials, have led to renewed interest from the pharmaceutical industry in anti-infective development. For example, the Food and Drug Administration Safety and Innovation Act became law in 2012 and included the Generating Antibiotic

Incentives Now Act, or the GAIN Act, which provides incentives, including access to expedited FDA review for approval, fast track designation and five years of potential data exclusivity extension for the development of new QIDPs.

As a result of increasing resistance to antibiotics and the wide array of potential pathogens that cause CABP, the current standard of care for hospitalized patients with CABP whose treatment is initiated in the hospital usually involves first-line empiric treatment with a combination of antibiotics to address all likely bacterial pathogens or monotherapy with a fluoroquinolone antibiotic. Combination therapy presents the logistical challenge of administering multiple drugs with different dosing regimens and increases the risk of drug-drug interactions and the potential for serious side effects. Fluoroquinolones are associated with safety and tolerability concerns, including a relatively high risk for developing Clostridium difficile infections. In addition, in May 2016, the FDA announced that an FDA safety review has shown that fluoroquinolones, when used systemically, in the form of tablets, capsules and injectable, are associated with disabling and potentially permanent serious side effects that can occur together. These side effects can involve the tendons, muscles, joints, nerves, and central nervous system. Fluoroquinolones are typically administered in combination with other antibiotics, if community-acquired MRSA is suspected. In addition, many currently available antibiotic therapies are only available for IV administration and are prescribed for seven to 14 days, meaning continued treatment requires prolonged hospitalization or a switch to a different antibiotic administered orally, with the attendant risk that the patient might respond differently.

Effective January 1, 2017, the Joint Commission & Center for Medicare and Medicaid Services, or CMS, began requiring all U.S. hospitals to have Antibiotic Management guidelines, also known as Stewardship Committees, in place to identify antibiotics most appropriate and targeted to each individual patients infection. Past efforts to cast the widest net possible with broad-spectrum antibiotics that affect many types of bacteria have caused problems, such as C. difficile infections, by killing good bacteria or increased antibiotic resistance in other bacteria in different areas of the body. Additionally, in 2016, the Infectious Disesase Society of America and the Society for Healthcare Epidemiology of America, or IDSA/SHEA, updated their Antibiotic Stewardship guidelines for antibiotic use. We believe that three key goals from these guidelines are applicable to the treatment of CABP:

·Reduce the risk of antibiotics associated with a high risk of C. difficile infections;

·Increase use of oral antibiotics as a strategy to improve outcomes or decrease costs; and

·Reduce antibiotic therapy to the shortest effective duration.

Pleuromutilins are semi-synthetic compounds derived from a naturally occurring antibiotic and inhibit bacterial growth by binding to a specific site on the bacterial ribosome that is responsible for bacterial protein synthesis. We have developed an understanding of how to optimize characteristics of the pleuromutilin class, such as antimicrobial spectrum, potency, absorption following oral administration and tolerability, which in turn led to our selection and development of lefamulin, our lead product candidate. We have completed a Phase 2 clinical trial for ABSSSI in which IV lefamulin achieved a high cure rate against multi-drug resistant Gram-positive bacteria, including MRSA. In addition, in preclinical studies, lefamulin showed potent antibacterial activity against a variety of Gram-positive bacteria, Gram-negative bacteria and atypical bacteria, including multi-drug resistant strains.

The preclinical studies and clinical trials we have conducted to date suggest that lefamulins novel mechanism of action is responsible for the lack of cross resistance observed with other antibiotic classes and a low propensity for development of bacterial resistance to lefamulin. As a result of the favorable safety and tolerability profile we have observed in our clinical trials to date, we believe lefamulin has the potential to present fewer complications relative to the use of current therapies. Based on our research, we also believe that the availability of both IV and oral formulations of lefamulin, and an option to switch to oral treatment, could reduce the length of a patients hospital stay and the overall cost of care.

We have evaluated lefamulin in more than 440 patients and subjects in seventeen completed Phase 1 clinical trials and a Phase 2 clinical trial in ABSSSI. In our Phase 1 clinical trials, we have characterized the clinical pharmacology of the IV formulation of lefamulin and shown oral bioavailability of a tablet formulation of lefamulin with rapid tissue distribution, including substantial penetration into lung fluids and lung immune cells. In our Phase 2 clinical trial evaluating the safety and efficacy of two different doses of the IV formulation

of lefamulin administered over five to 14 days compared to the antibiotic vancomycin in patients with ABSSSI, the clinical success rate at test of cure, or TOC, for lefamulin was similar to that of vancomycin. Lefamulin has been well tolerated in all our clinical trials to date when administered by IV and oral routes. The frequency of adverse events that we observed in our Phase 2 clinical trial in ABSSSI was similar for patients treated with IV lefamulin and patients treated with vancomycin.

Based on the clinical results of lefamulin for the treatment of ABSSSI, as well as its rapid tissue distribution, including substantial penetration into the lung, we are evaluating lefamulin for the treatment of moderate to severe CABP in two international Phase 3 clinical trials. We are initially pursuing the development of lefamulin for CABP because of the limited development of new antibiotic classes for this indication over the past 15 years, our belief that there exists a significant unmet medical need for a first-line empiric monotherapy that addresses the growing development and spread of bacterial resistance, as well as recently clarified FDA guidance regarding the approval pathway. We initiated the first of these trials in September 2015 and the second trial in April 2016. We are also further characterizing the clinical pharmacology of lefamulin in several additional Phase 1 clinical trials.

We plan to pursue a number of additional opportunities for lefamulin, including beginning a development program for use in pediatric patients and potentially for the treatment of ABSSSI. In addition, as an antibiotic with potent activity against a wide variety of multi-drug resistant pathogens, including MRSA, we may explore development of lefamulin in other indications, including ventilator-associated bacterial pneumonia, or VABP, hospital-acquired bacterial pneumonia, or HABP, sexually transmitted infections, or STIs, osteomyelitis and prosthetic joint infections. Through our research and development efforts, we have also identified a topical pleuromutilin product candidate, BC-7013, which has completed a Phase 1 clinical trial.

We own exclusive, worldwide rights to lefamulin. Lefamulin is protected by issued patents in the United States, Europe and Japan covering composition of matter, which are scheduled to expire no earlier than 2028. We also have been granted patents for lefamulin relating to process and pharmaceutical crystalline salt forms in the United States, which are scheduled to expire no earlier than 2031. In addition, we own a family of pending patent applications directed to pharmaceutical compositions of lefamulin, which if issued would be scheduled to expire no earlier than 2036.

Our Strategy

Our goal is to become a fully integrated biopharmaceutical company focused on the research, development and commercialization of novel anti-infective products. The key elements of our strategy to achieve this goal are:

·Complete Phase 3 clinical development of lefamulin for CABP. We are devoting a significant portion of our financial resources and business efforts to completing the clinical development of lefamulin for the treatment of CABP. We initiated two international Phase 3 clinical trials of lefamulin for the treatment of moderate to severe CABP. We initiated the first of these trials in September 2015 and the second trial in the April 2016. Based on our estimates regarding patient enrollment, we expect to have top-line data from LEAP 1 in the third quarter of 2017. With respect to LEAP 2, based on current projections, we expect to complete patient enrollment in the fourth quarter of 2017, and we anticipate receiving top-line data for LEAP 2 in the first quarter of 2018. If the results of these trials are favorable, including achievement of the primary efficacy endpoints of the trials, we expect to submit applications for marketing approval for lefamulin for the treatment of CABP in both the United States and Europe in 2018.

·Maximize the commercial potential of lefamulin for CABP. We own exclusive, worldwide rights to lefamulin. We expect that our initial target patient population for lefamulin will consist of patients with moderate to severe CABP. If lefamulin receives marketing approval from the FDA for the treatment of CABP, we plan to commercialize it in the United States with our own targeted hospital sales and marketing organization that we plan to establish. We believe that we will be able to effectively communicate lefamulins differentiating characteristics and key attributes to clinicians and hospital pharmacies with the goal of establishing favorable formulary status for lefamulin. If lefamulin receives marketing approval outside the United States for the treatment of CABP, we expect to utilize a variety of types of collaboration, distribution and other marketing arrangements

with one or more third parties to commercialize lefamulin in such markets. We also are conducting pediatric formulation development activities to support clinical trials of lefamulin for pediatric use for CABP.

·Pursue the continued development of lefamulin in additional indications. We plan to pursue the continued development of lefamulin for indications in addition to CABP. For example, we are conducting formulation development activities for lefamulin for use in pediatric patients, and potentially for the treatment of ABSSSI. In addition, we are evaluating whether to pursue studies of lefamulin in patients with VABP or HABP. We believe that lefamulins product profile also provides the opportunity to expand to other indications beyond pneumonia. For example, investigation of the tolerability of higher single doses of lefamulin could also support use of lefamulin for the treatment of STIs. In addition, we may explore longer duration of treatment with lefamulin to support development of a treatment for osteomyelitis and prosthetic joint infections. We believe that lefamulin would be differentiated from other treatment options for each of these potential uses because of lefamulins novel mechanism of action, spectrum of activity, including activity against multi-drug resistant pathogens, achievement of substantial concentrations in relevant tissues, availability as both an IV and oral formulation and favorable safety and tolerability profile.

·Advance the development of other pleuromutilin product candidates and possibly compounds in other classes. We are currently focused on developing additional pleuromutilin product candidates through our deep understanding of this class of antibiotics. Our product candidate BC-7013 has completed a Phase 1 clinical trial. We believe that this pleuromutilin compound is well suited for the topical treatment of a variety of Gram-positive infections, including uncomplicated skin and skin structure infections, or uSSSIs. Furthermore, we own diverse libraries of compounds in other antibacterial classes, such as ß-lactams and acremonic acids, which are a potential basis for the discovery and development of novel antibacterial agents.

·Evaluate business development opportunities and potential collaborations. We plan to evaluate the merits of entering into collaboration agreements with other pharmaceutical or biotechnology companies that may contribute to our ability to efficiently advance our product candidates, build our product pipeline and concurrently advance a range of research and development programs. Potential collaborations may provide us with funding and access to the scientific, development, regulatory and commercial capabilities of the collaborators. We also plan to encourage local and international government entities and non-government organizations to provide additional funding and support for our development programs. We may expand our product pipeline through opportunistically in-licensing or acquiring the rights to complementary products, product candidates and technologies for the treatment of a range of infectious diseases.

The following table summarizes the indications for which we are developing our product candidates and the status of development.

DEVELOPMENT STAGE

*We have initiated two international Phase 3 clinical trials of lefamulin for the treatment of moderate to severe CABP. However, we have not previously conducted any clinical trials of lefamulin specifically for CABP. Our completed Phase 2 clinical trial evaluated lefamulin in patients with ABSSSI. We have obtained input from the FDA and select European authorities, including reaching agreement with the FDA on a Special Protocol Assessment, or SPA, regarding the study design of our first Phase 3 clinical trial, in anticipation of submitting applications for marketing approval for lefamulin for the treatment of CABP in both the United States and Europe in 2018.

Background

Anti-Bacterial Market and Scientific Overview

Bacteria are broadly classified as Gram-positive or Gram-negative. Gram-positive bacteria possess a single membrane and a thick cell wall and turn dark-blue or violet when subjected to a laboratory staining method known as Grams method. Gram-negative bacteria have a thin cell wall layered between an inner cytoplasmic cell membrane and a bacterial outer membrane and, as a result, do not retain the violet stain used in Grams method. Antibiotics that are active against both Gram-positive and Gram-negative bacteria are referred to as broad spectrum, while those that are active only against a select subset of Gram-positive or Gram-negative bacteria are referred to as narrow spectrum. Bacteria that cause infections are often referred to as bacterial pathogens. Because it often takes from 24 to 48 hours to definitively diagnose the particular bacterial pathogen causing an infection, the causative pathogen often remains unidentified and narrow spectrum antibiotics are not generally used as empiric monotherapy for first-line treatment of hospitalized patients with serious infections.

Since the introduction of antibiotics in the 1940s, numerous new antibiotic classes have been discovered and developed for therapeutic use. The development of new antibiotic classes and new antibiotics within a class is important because of the ability of bacteria to develop resistance to existing mechanisms of action of currently approved antibiotics. However, the pace of discovery and development of new antibiotic classes slowed considerably in the past few decades. The CDC estimates that the pathogens responsible for more than 70% of U.S. hospital infections are resistant to at least one of the antibiotics most commonly used to treat them. The CDC also estimated in 2013, based on data collected from evaluations performed between 2006 and 2011, that annually in the United States at least two million people become infected with bacteria that are resistant to antibiotics and at least 23,000 people die as a direct result of these infections.

Antibiotic resistance is primarily caused by genetic mutations in bacteria selected by exposure to antibiotics that do not kill all of the bacteria. In addition to mutated bacteria being resistant to the drug used for treatment, many bacterial strains can also become cross-resistant, meaning that they become resistant to multiple classes of antibiotics. As a result, the effectiveness of many antibiotics has declined, limiting physicians options to treat serious infections and exacerbating a global health issue. For example, the WHO estimated in 2014 that people with infections caused by MRSA, a highly resistant form of bacteria, are 64% more likely to die than people with a non-resistant form of the infection. Resistance can increase the cost of healthcare because of the potential for lengthier hospital stays and more intensive care. Growing antibiotic resistance globally, together with the low level of investment in research and development, is considered one of the biggest global health threats. In 2010, the WHO stated that antibiotic resistance is one of the three greatest threats to human health. Partially in response to this threat, the U.S. Congress passed the GAIN Act in 2012, which provides incentives, including access to expedited FDA review for approval, fast track designation and five years of potential data exclusivity extension for the development of new QIDPs. Additional legislation is also being considered in the United States, including the Antibiotic Development to Advance Patient Treatment Act of 2013, which is intended to accelerate the development of anti-infective products, and the Developing an Innovative Strategy for Antimicrobial Resistant Microorganisms Act of 2014, which is intended to establish a new reimbursement framework to enable premium pricing of anti-infective products.

In 2009, sales of antibiotics totaled approximately $42 billion globally. Although judicious use of antibiotics is important to reduce the rate of antibiotic resistance, this approach alone cannot fully address the threat from increasing antibiotic resistance. New antibiotics, and particularly new antibiotic classes, are needed to ensure the availability of effective antibiotic therapy in the future.

Community-Acquired Bacterial Pneumonia (CABP)

Market Overview

The WHO estimated in 2002 that there were approximately 450 million pneumonia cases reported per year worldwide, causing approximately 4.0 million deaths in 2002. According to an article published in 2011 in the peer-reviewed medical journal Therapeutic Advances in Respiratory Disease, the annual incidence of community-acquired pneumonia is between five and 11 cases per 1,000 people, with the incidence rate rising in elderly patients. In a study published in 2004 in the peer-reviewed medical journal Clinical Infectious Diseases in which more than 46,000 people in the state of Washington were monitored over three years, the incidence of CABP among those 65 to 69 years of age was 18.2 cases per 1,000 people per year and increased to 52.3 cases per 1,000 people per year in those over 85 years of age.

The U.S. National Center for Health Statistics estimated that between 1988 and 1994 there were approximately 5.6 million cases of pneumonia per year in the United States. More recently, based on our combined analysis of the CDCs 2007 National Ambulatory Medical Care Survey, the National Hospital Ambulatory Medical Care Survey and 2013 data from the Healthcare Cost and Utilization Project we estimate that over 5.0 million adults are treated annually for CABP in the United States and that the majority of these adult CABP patients have their treatment initiated in a hospital, including emergency departments. According to the Healthcare Cost and Utilization Project, or HCUP, in 2013, approximately 3.1 million adults sought treatment in a U.S. hospital for CABP. In addition, in 2013, approximately 2.4 million adults were admitted to U.S. hospitals for in-patient care with a diagnosis of CABP and approximately 700,000 adults were seen in an emergency department at U.S. hospitals for treatment of CABP and then released.

Additionally, in 2014, based on CDC data approximately 50,000 patients died from CABP in the United States. Based on data collected from July 1, 2012 through June 30, 2015, on the Medicare.gov Hospital Compare website, the current national rate of readmissions for Medicare pneumonia patients is 17.1%, which is the percentage of patients who have had a recent hospital stay that must return to a hospital for unplanned care within 30 days of being discharged. The national average death rate for Medicare pneumonia patients, excluding Medicare Advantage plan data, is 16.3%, which is the percentage of patients who die, for any reason, within 30 days of admission to a hospital.

Based on data from Arlington Medical Resources, or AMR, a leading provider of medical data from hospitals and other healthcare facilities, who reported that the number of antibiotic treatment courses for CABP adult patients in hospitals in the United States exceeded 6.8 million for full-year 2015, we estimate approximately 5.3 million of these CABP courses were for IV/injectable antibiotics for adult CABP patients,

while approximately 1.5 million CABP oral antibiotic courses were prescribed for adult CABP patients in the hospital setting. Additionally, for the twelve months ending September 30, 2016, Source Health Solutions estimates that once adult CABP patients are discharged home from U.S. hospitals, approximately 4.2 million antibiotic oral prescriptions are written annually for their outpatient antibiotic treatment. Relative to the approximately 6.6 million adult CABP outpatient oral antibiotic prescriptions that Health Source Solutions estimates are written over the same time-period, approximately 6 out of every 10 oral antibiotic prescriptions for adult CABP results as a transition of care from hospital-initiated treatment to outpatient therapy. The remaining CABP prescriptions originate from prescribers in community clinics, primary care offices and at other non-hospital based sites of urgent care.

Causes of CABP

Pneumonia can be caused by a variety of micro-organisms, with bacteria being the most common identifiable cause. CABP refers to bacterial pneumonia that is acquired outside of a hospital setting. Signs and symptoms of CABP include cough, fever, sputum production and chest pain. A number of different types of bacteria can cause CABP, including both Gram-positive and Gram-negative bacteria. Pneumonia that is caused by atypical bacterial pathogens often has different symptoms and responds to different antibiotics than pneumonia caused by pathogens referred to as typical bacteria. However, atypical bacteria are not uncommon. The most common bacterial pathogens noted in current treatment guidelines from the Infectious Diseases Society of America, or IDSA, for hospitalized CABP patients who are not in the intensive care unit are Streptococcus pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae, Chlamydophila pneumoniae, and Legionella species. In addition, IDSA notes the emergence of resistance to commonly utilized antibiotics for CABP, specifically drug-resistant S. pneumoniae and community-acquired MRSA, or CA-MRSA, as a major consideration in choosing empiric therapy. However, a majority of patients do not have a pathogen identified using routine diagnostic tests available to physicians.

Currently Available Treatment Options

In 2007, based on the most likely bacteria to cause CABP, IDSA and the American Thoracic Society, or ATS, recommend empiric treatment of hospitalized patients with CABP who do not require treatment in an intensive care unit with either:

·a combination of a cephalosporin, an antibiotic that disrupts the cell wall of bacteria, plus a macrolide, an antibiotic that disrupts bacterial protein synthesis; or

·monotherapy with a respiratory fluoroquinolone, an antibiotic that disrupts bacterial protein synthesis.

In the event CA-MRSA is suspected, these guidelines recommend that vancomycin, an antibiotic that disrupts the cell wall of bacteria, or linezolid, an antibiotic that disrupts bacterial protein synthesis, be used or added to the current regimen.

In addition, physicians need to be aware of the local susceptibility profiles of the common bacterial pathogens associated with CABP because of increasing resistance to first-line antibiotics. For example, rates of pneumococcal resistance to recommended first-line macrolides exceed 40% in some areas, while resistance in M. pneumoniae associated with severe disease has been recently reported by the CDC in the United States.

Limitations of Currently Available Treatment Options

When confronted with a new patient suffering from a serious infection caused by an unknown pathogen, a physician may be required to quickly initiate first-line empiric antibiotic treatment, often with a combination of antibiotics, to stabilize the patient prior to definitively diagnosing the particular bacterial infection. However, currently available antibiotic therapies for first-line empiric treatment of CABP suffer from significant limitations.

As a result of bacterial resistance, the effectiveness of many antibiotics has declined. For example, the CDC estimates that in 30% of severe S. pneumoniae cases, the bacterial pathogen is fully resistant to one or more clinically relevant antibiotics, with 44% of strains resistant to a macrolide in the United States. In addition, fluoroquinolone resistance in S. pneumoniae has increased from less than 0.5% to more than 3% of cases in some regions of North America, which parallels increased total fluoroquinolone prescriptions. Antibiotic resistance has a significant impact on mortality and contributes heavily to healthcare system costs worldwide. According to the CDC, cases of resistant pneumococcal pneumonia result in 32,000 additional doctor visits, approximately 19,000 additional hospitalizations and 7,000 deaths each year. These cases are associated with $96 million in excess medical cost per year in the United States. IDSA/ATS guidelines recommend empiric treatment that provides broad spectrum antimicrobial coverage. None of the currently available treatment options provides a spectrum of antibacterial coverage as a monotherapy that sufficiently covers all of the most common bacterial causes of CABP, including multi-drug resistant strains.

Difficult, Inconvenient and Costly Regimens

Currently available antibiotics used to treat CABP and other serious infections can be difficult, inconvenient and costly to administer. Physicians typically prefer IV administration for patients hospitalized with more serious illness to ensure adequate delivery of the drug rapidly. Many IV antibiotics are prescribed for seven to 14 days or more and patients can be hospitalized for much or all of this period or require in-home IV therapy. The diagnosis related group, or DRG, reimbursement system often used in the U.S. hospital setting pays a fixed fee for an episode of CABP that may not fully compensate hospitals for the duration of hospitalized care. Prolonged IV treatment that extends the period of hospitalization may cause hospital costs to increase in excess of the fixed reimbursement fee, resulting in significant negative impact on healthcare institutions. In addition, to address all likely bacterial pathogens in a patient with a more serious illness, IDSA guidelines recommend using a combination of antibiotics. Combination therapy presents the logistical challenge of administering multiple drugs with different dosing regimens and increases the risk of drug-drug interactions. While IV treatment delivers the drug more rapidly than is possible orally, once a patient is stabilized, oral treatment with the same drug would allow for more convenient and cost-effective out-patient treatment. Because many commonly used antibiotics are only available in IV form, a switch to an oral therapy requires changing to a different antibiotic, which may be less effective for the patient.

Adverse Effects

Currently available antibiotic therapies can have serious side effects. These side effects may include severe allergic reaction, decreased blood pressure, nausea and vomiting, suppression of platelets, pain and inflammation at the site of injection, muscle, renal and oto-toxicities, optic and peripheral neuropathies and headaches. At times, these side effects may be significant and require discontinuation of therapy. As a result, some treatments require clinicians to closely monitor patients blood levels and other parameters, increasing the expense and inconvenience of treatment. This risk may be increased with combination therapy, which exposes patients to potential adverse effects from each of the antibiotics used in treatment. For example, fluoroquinolones are associated with tendon rupture and peripheral neuropathy. In addition, fluoroquinolones have been associated with an increased frequency of C. difficile colitis, an overgrowth of a bacteria in the colon that produces a toxin that results in inflammation of the colon and repeated bouts of watery diarrhea. This has resulted in limitations on the use of fluoroquinolones in several countries. In November 2015, the FDA convened an Advisory Committee meeting to review the benefits and risks of fluoroquinolones in less severe indications, such as uncomplicated UTI, acute bacterial sinusitis and acute bacterial exacerbations of chronic bronchitis. Based on the committees recommendation, in July 2016, the FDA approved changes to the labels of fluoroquinolones to indicate that fluoroquinolones should be reserved for use in patients who have no other treatment options for the indications mentioned above, because the risk of these serious side effects generally outweighs the benefits in these patients. These changes included a requirement that a separate patient Medication Guide be given with each prescription that describes the safety issues associated with this class of drugs.

We are developing lefamulin to be the first pleuromutilin antibiotic available for systemic administration in humans. Lefamulin is a semi-synthetic derivative of the naturally occurring antibiotic, pleuromutilin, which was originally identified from a fungus called Pleurotus mutilis. Lefamulin inhibits the synthesis of bacterial protein, which is required for bacteria to grow. Lefamulin acts by binding to the peptidyl transferase center, or PTC, on the bacterial ribosome in such a way that it interferes with the interaction of protein production at two key sites known as the A site and the P site, resulting in the inhibition of bacterial proteins and the cessation of bacterial growth. Lefamulins binding occurs with high affinity, high specificity and at molecular sites that are different than other antibiotic classes. We believe that lefamulins novel mechanism of action is responsible for the lack of cross-resistance with other antibiotic classes that we have observed in our preclinical studies and clinical trials and a low propensity for development of bacterial resistance to lefamulin. The binding of lefamulin to the PTC on the bacterial ribosome is depicted in the graphic below.

We are developing both IV and oral formulations of lefamulin. We believe that lefamulin is well suited to be used empirically as monotherapy for the treatment of respiratory tract infections, such as CABP, because of its spectrum of antibacterial activity against both the typical and atypical pathogens causing CABP, including multi-drug resistant pathogens such as MRSA. In preclinical studies and in Phase 1 clinical trials, lefamulin achieved substantial concentrations in the epithelial lining fluid, or ELF, of the lung, the site infected during pneumonia. Lefamulin also provides the ability to switch from IV to oral therapy with the same active ingredient.

We have completed a Phase 2 clinical trial of lefamulin for ABSSSI. Based on the clinical results of lefamulin for ABSSSI, as well as its rapid tissue distribution, including substantial penetration into lung fliuds and lung immune cells, we initiated two international, pivotal Phase 3 clinical trials of lefamulin for the treatment of moderate to severe CABP. These are the first clinical trials we have conducted with lefamulin for the treatment of CABP. We initiated the first of these trials in September 2015 and the second trial in April 2016. We designed these trials to follow draft guidance published by the FDA for the development of drugs for CABP and guidelines from the EMA for the development of antibacterial agents, as well as our SPA with the FDA regarding the study design of our first Phase 3 clinical trial. According to the draft FDA guidance and FDA feedback, either a Phase 3 clinical trial for CABP, supported by evidence of antibacterial activity accrued during a clinical development program for another indication, such as ABSSSI, or two Phase 3 clinical trials for CABP, may provide sufficient evidence of efficacy in CABP.

Based on our estimates regarding patient enrollment, we expect to have top-line data from LEAP 1 in the third quarter of 2017. With respect to LEAP 2, based on current projections, we expect to complete patient enrollment in the fourth quarter of 2017, and we anticipate receiving top-line data for LEAP 2 in the first quarter of 2018. If the results of these trials are favorable, including achievement of the primary efficacy endpoints of the trials, we expect to submit applications for marketing approval for lefamulin for the treatment of CABP in both the United States and Europe in 2018. We submitted to the FDA an investigational new drug application, or IND, for the IV formulation of lefamulin in September 2009 and an IND for the oral formulation of lefamulin in January 2015. The FDA has designated each of the IV and oral formulations of lefamulin as a QIDP and also granted fast track designations to each of these formulations of lefamulin.

We believe that the combination of the following key attributes of lefamulin, observed in clinical trials and preclinical studies, differentiates lefamulin from currently available antibiotics and make lefamulin well suited for use as a first-line empiric monotherapy for the treatment of CABP.

Broad Spectrum of Activity and Low Propensity for the Development of Bacterial Resistance

We expect lefamulins spectrum of antibacterial activity against typical and atypical pathogens could eliminate the need to use a combination of antibiotics for the treatment of CABP. In our completed Phase 2 clinical trial, IV lefamulin achieved a high cure rate against multi-drug resistant Gram-positive bacteria, including MRSA. In addition, in preclinical studies, lefamulin showed activity against a variety of Gram-positive bacteria, including S. pneumoniae and S. aureus, that are resistant to other classes of antibiotics, Gram-negative bacteria, including H. influenzae and M. catarrhalis, and atypical bacteria, including C. pneumoniae, M. pneumoniae and L. pneumophila. Included in lefamulins spectrum of activity are all bacterial pathogens identified by IDSA as the most common causes of CABP for hospitalized patients who are not in the intensive care unit, as well as strains of the above listed bacteria that are resistant to other classes of antibiotics, including penicillins, cephalosporins, fluoroquinolones and macrolides.

Based on observations from our preclinical studies and clinical trials of lefamulin, as well as industry experience with pleuromutilins used in veterinarian medicine over the last 30 years, we believe that lefamulins novel mechanism of action is responsible for the lack of cross-resistance observed with other antibiotic classes and a low propensity for development of bacterial resistance to lefamulin.

We have developed both an IV and oral formulation of lefamulin, which we are utilizing in our Phase 3 clinical trials of lefamulin for the treatment of CABP. The administration of lefamulin as a monotherapy avoids the need for the complicated dosing regimens typical of multi-drug cocktails. We believe the availability of both IV and oral administration, and an option to switch to oral treatment, would be more convenient for patients and could reduce the length of a patients hospital stay and the overall cost of care. The potential reduction in the overall cost of care could be particularly meaningful to healthcare institutions, as the DRG reimbursement system pays a fixed fee for the treatment of CABP regardless of the length of hospital stay. We believe that our Phase 3 trial design will permit us to submit for approval of both IV and oral formulations of lefamulin, subject to obtaining favorable results, including achievement of the primary efficacy endpoints of the trials.

Favorable Safety and Tolerability Profile

We have evaluated lefamulin in over 440 subjects and patients in our completed Phase 1 and Phase 2 clinical trials. In these trials, lefamulin has exhibited a favorable safety and tolerability profile. In our Phase 2 clinical trial of lefamulin, no patient suffered any serious adverse events that were determined to be related to lefamulin, and safety and tolerability were comparable to vancomycin, the control therapy in the trial. In addition, no clinically significant change in electrocardiogram, or ECG, was measured, and no drug-related cardiovascular adverse events were reported. Furthermore, we believe the use of lefamulin as a monotherapy would present fewer potential complications relative to the use of multiple antibiotics as combination therapy. We are also continuing to evaluate the safety and tolerability of lefamulin in our Phase 3 clinical trials.

Phase 3 Clinical Trials

We are conducting a pivotal clinical trial program of lefamulin for the treatment of CABP consisting of two international Phase 3 clinical trials. We initiated the first of these trials in September 2015 and the second

trial in April 2016. We designed these trials to comply with the guidelines of The International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use, which are currently used as guidance by the FDA, and good clinical practices. We are conducting these trials at centers in the United States, Europe, Asia and selected countries in the southern hemisphere. We are currently enrolling patients in each of these clinical trials in several countries and are continuing with the regulatory steps necessary to initiate and conduct these trials, including submission of the trial protocol and relevant information about lefamulin to local regulatory authorities and ethics review committees in other countries.

First Phase 3 Clinical Trial

We designed our Phase 3 clinical trials to follow the draft guidance published by the FDA for the development of drugs for CABP and guidance from the EMA for the development of antibacterial agents with the goal of positioning lefamulin as a first-line empiric monotherapy for the treatment of CABP. We reached agreement with the FDA in September 2015 on a SPA regarding the study design for our first Phase 3 clinical trial and obtained input from select European authorities in anticipation of submitting a new drug application with the FDA and a marketing authorization application, or MAA, with the EMA, in each case, for the treatment of CABP. In April 2016, we reached agreement with the FDA regarding an amendment to the SPA. We also plan to conduct a number of studies to support FDA approval of lefamulin, including studies in patients with hepatic insufficiency and renal impairment. If we complete the two Phase 3 clinical trials of lefamulin when we anticipate and obtain favorable results, we expect to submit an NDA to the FDA and an MAA to the EMA in 2018.

Our first Phase 3 clinical trial of lefamulin for the treatment of CABP is a multi-center, randomized, controlled, double-blind study comparing lefamulin to moxifloxacin, a fluoroquinolone antibiotic. Linezolid (or matching placebo for the lefamulin arm), can be added to treatment if an investigator suspects that a patient is infected with MRSA prior to randomization, as moxifloxacin is not approved to treat MRSA. This trial is designed to assess the non-inferiority of lefamulin compared to moxifloxacin, with or without linezolid. We expect the study population will include male and female patients of at least 18 years of age. Our study design targets the enrollment of approximately 550 patients, of which we expect a small proportion will require linezolid to be added.

Lefamulin will be dosed at 150 mg IV every 12 hours. The comparator drugs will be dosed according to their approved labeling, with moxifloxacin dosed at 400 mg IV daily and linezolid at 600 mg IV every 12 hours. Based on pre-defined criteria, investigators will have the option to switch patients to oral therapy after three days (at least six doses) of IV study medication. Lefamulin will be administered orally as one 600 mg tablet every 12 hours, moxifloxacin at 400 mg daily and linezolid at 600 mg every 12 hours. Based on the pharmacokinetic profile of lefamulin, we expect oral dosing of one 600 mg tablet every 12 hours to have a similar therapeutic benefit as IV dosing of 150 mg every 12 hours.

All patients enrolled in this trial will be classified as Pneumonia Outcomes Research Team, or PORT, severity of at least 3 on a scale of 1 to 5, which corresponds to moderate to severe clinical disease. Patients who have previously taken no more than one dose of a short acting, potentially effective antibiotic for the treatment of the current CABP episode within 24 hours of receiving the first dose of study medication will be allowed to participate in the trial but will comprise only up to 25% of the total intent to treat, or ITT, population. Patients with confirmed S. aureus bacteremia will be discontinued from the trial. Investigators will obtain baseline Grams stain and culture of suitable specimens from the site of infection. Patients will be treated for a minimum seven days and a maximum of ten days.

We will assess patients between 72 and 120 hours from the start of treatment, at the end of treatment, or EOT, within 48 hours of administration of the final dose of study medication, at a TOC visit between five and ten days after administration of the final dose of study medication and at a telephone follow-up 30 days after administration of the first dose of study medication.

We will evaluate the following patient subsets:

·an ITT population consisting of all randomized patients regardless of whether they have received study medication;

·a modified intent to treat, or MITT, population consisting of all randomized subjects who receive any amount of study drug;

·a microbiological intent to treat, or microITT, population consisting of all subjects in the ITT population who have at least one baseline bacterial pathogen known to cause CABP, Legionella pneumophila from an appropriate microbiological specimen, or CABP caused by Mycoplasma pneumoniae or Chlamydophila pneumoniae;

·a clinically evaluable, or CE, population which is a subset of the ITT population that will include subjects who meet the criteria for CABP and who have received at least the pre-specified minimal amount of the intended dose of study drug and duration of treatment, do not have an indeterminate response based on the investigators assessment of clinical response at EOT for the CE-EOT population and at TOC for the CE-TOC population, did not receive concomitant antibacterial therapy, other than adjunctive linezolid, that is potentially effective against CABP pathogens (except in the case of clinical failure) from the first dose of study drug through the EOT visit for the CE-EOT population and through the TOC visit for the CE-TOC population, and for whom there are no other confounding factors that interfere with the assessment of the outcome; and

·a microbiologically evaluable, or ME, population consisting of all subjects who meet the criteria for inclusion in both the microITT, CE-EOT and ME-EOT populations or the CE-TOC and ME-TOC populations.

The primary efficacy endpoint for the trial for the FDA is the proportion of patients in the ITT population for each of the lefamulin treatment group and the moxifloxacin treatment group who are alive, have improvement in at least two of the four cardinal symptoms of CABP as outlined in the current FDA guidance, have no worsening in any of the four cardinal symptoms of CABP and have not received a concomitant antibiotic (other than linezolid) for the treatment of CABP up through 120 hours after the first dose of lefamulin. This endpoint is also referred to as early clinical response. The four cardinal symptoms of CABP, as outlined in the current FDA guidance, are difficulty breathing, cough, production of purulent sputum and chest pain.

The primary efficacy endpoint for the EMA is the clinical success rate at the TOC visit for lefamulin in both the CE and MITT populations compared to moxifloxacin. Clinical success is based on the investigators assessment that a patient has clinically responded to lefamulin, which means that the patient has complete resolution or significant improvement of all local and systemic signs and symptoms of infection such that no additional antibiotic treatment is administered for the treatment of the current episode of CABP.

Key secondary efficacy and exploratory endpoints for our first Phase 3 clinical trial include the following:

·assessment of response for the primary efficacy outcome of early clinical response (the FDA primary endpoint) in the microITT population;

·assessment of response in each treatment group with an investigator assessment of clinical response at TOC (the EMA primary endpoint) in the microITT and ME-TOC populations;

·assessment of the microbiological response by pathogen for the microITT and ME-TOC populations at TOC; and

·assessment of all-cause mortality through day 28 in the ITT population.

In April 2016, we reached an agreement with the FDA under the Special Protocol Assessment procedure to amend the design of our first Phase 3 clinical trial of lefamulin for the treatment of CABP. The amendment to the SPA followed discussions with the FDA regarding the design of our second Phase 3 clinical trial of lefamulin as well as discussions regarding the overall Phase 3 development program for lefamulin for the treatment of CABP. We believe the design of the study remains within the parameters set forth in the FDA Guidance for Industry Community-Acquired Bacterial Pneumonia: Developing Drugs for Treatment. Key amendments to the study include:

·modify the non-inferiority margin of the primary FDA endpoint of early clinical response from 10% to 12.5%;

·reduce the total number of patients to be enrolled in the study from 740 to as low as 550 as a result of a revision of the non-inferiority margin;

·simplify the treatment regimens; and

·increase the duration of therapy from a minimum of five days to a minimum of seven days.

In December 2016, we reached an enrollment target of 60% in our first Phase 3 clinical trial, and in February 2017, we received a recommendation from an independent interim analysis committee that we continue the trial with no adjustment to its sample size.

Second Phase 3 Clinical Trial

Our second Phase 3 clinical trial of lefamulin for the treatment of CABP is a multi-center, randomized, controlled, double-blind study comparing oral lefamulin to moxifloxacin, a fluoroquinolone antibiotic. This trial is designed to assess the non-inferiority of oral lefamulin compared to moxifloxacin. We expect the study population will include male and female patients of at least 18 years of age. We are targeting the enrollment of approximately 738 patients in this trial.

Lefamulin will be dosed orally at 600mg every 12 hours. The comparator drug moxifloxacin will be dosed according to approved labeling at 400 mg daily. All medications will be administered according to a double-blind and double-dummy design.

All patients enrolled in this trial will be classified as PORT severity of at least 2 and no greater than 4 on a scale of 1 to 5 which corresponds to moderate disease. Patients who have previously taken no more than one dose of a short acting, potentially effective antibiotic for the treatment of the current CABP episode within 24 hours of receiving the first dose of study medication will be allowed to participate in the trial but will comprise only up to 25% of the total intent to treat, or ITT, population. Investigators will obtain baseline Grams stain and culture of suitable specimens from the site of infection. Patients will be treated for five days with lefamulin or for seven days with moxifloxacin. We will assess patients between 72 and 120 hours from the start of treatment, at the end of treatment, or EOT, within 48 hours of administration of the final dose of study medication, at a TOC visit between five and ten days after administration of the final dose of study medication and at a telephone follow-up 30 days after administration of the first dose of study medication.

We will evaluate the following patient subsets:

·an ITT population consisting of all randomized patients regardless of whether they have received study medication;

·a MITT population consisting of all randomized subjects who receive any amount of study drug;

·a microITT, population consisting of all subjects in the ITT population who have at least one baseline bacterial pathogen known to cause CABP, Legionella pneumophila from an appropriate microbiological specimen, or CABP caused by Mycoplasma pneumoniae or Chlamydophila pneumoniae;

·a clinically evaluable, or CE, population which is a subset of the ITT population that will include subjects who meet the criteria for CABP and who have received at least the pre-specified minimal amount of the intended dose of study drug and duration of treatment, do not have an indeterminate response based on the investigators assessment of clinical response at EOT for the CE-EOT population and at TOC for the CE-TOC population, did not receive concomitant antibacterial therapy, other than adjunctive linezolid, that is potentially effective against CABP pathogens (except in the case of clinical failure) from the first dose of study drug through the EOT visit for the CE-EOT population and through the TOC visit for the CE-TOC population, and for whom there are no other confounding factors that interfere with the assessment of the outcome; and

·a microbiologically evaluable, or ME, population consisting of all subjects who meet the criteria for inclusion in both the microITT, CE-EOT and ME-EOT populations or the CE-TOC and ME-TOC populations.

The primary efficacy endpoint for the trial for the FDA is the proportion of patients in the ITT population for each lefamulin treatment group and the moxifloxacin treatment group who are alive, have improvement in at least two of the four cardinal symptoms of CABP as outlined in the current FDA guidance, have no worsening in any of the four cardinal symptoms of CABP and have not received a concomitant antibiotic for the treatment of CABP up through 120 hours after the first dose of lefamulin. This endpoint is also referred to as early clinical response.

The primary efficacy endpoint for the EMA is the clinical success rate at the TOC visit for lefamulin in both the CE and MITT populations compared to moxifloxacin. Clinical success is based on the investigators assessment that a patient has clinically responded to lefamulin, which means that the patient has complete resolution or significant improvement of all local and systemic signs and symptoms of infection such that no additional antibiotic treatment is administered for the treatment of the current episode of CABP.

Key secondary efficacy and exploratory endpoints for our second Phase 3 clinical trial include the following:

·assessment of response for the primary efficacy outcome of early clinical response (the FDA primary endpoint) in the microITT population;

·assessment of response in each treatment group with an investigator assessment of clinical response at TOC (the EMA primary endpoint) in the microITT and ME-TOC populations;

·assessment of the microbiological response by pathogen for the microITT and ME-TOC populations at TOC; and

·assessment of all-cause mortality through day 28 in the ITT population.

Completed Phase 2 Clinical Trial in ABSSSI

In 2011, we completed a multi-center, randomized, double-blind Phase 2 clinical trial in the United States evaluating the efficacy, safety and pharmacokinetics of the IV formulation of lefamulin compared to vancomycin in patients with ABSSSI. We selected ABSSSI as the indication for the trial to ensure that there would be a significant population of patients with multi-drug resistant Gram-positive bacteria. Gram-positive bacteria are the prevalent pathogens in ABSSSI. We selected vancomycin as the comparison therapy because vancomcyin is one of the antibiotics recommended by IDSA guidelines for the treatment of ABSSSI.

Trial Design

We enrolled 210 hospitalized patients with ABSSSI in the trial. The study population included male and female patients of at least 18 years of age and documented ABSSSI known or suspected to have been caused by a Gram-positive pathogen. Patients must have exhibited two signs of systemic inflammation or evidence of a significant underlying systemic or local medical condition at the time of enrollment and have required IV antibiotic therapy for the treatment of the ABSSSI.

We randomized patients on a 1:1:1 basis to three treatment groups to receive:

·100 mg of IV lefamulin every 12 hours;

·150 mg of IV lefamulin every 12 hours; or

·1,000 mg of IV vancomycin every 12 hours or otherwise dosed as local practice dictated based upon a patients kidney function.

Investigators obtained baseline Grams stain and culture of suitable specimens from the site of infection. We treated patients for a minimum of five days and a maximum of 14 days. We assessed patients on day 3, at the end of treatment within 24 hours of administration of the final dose of study medication, at a TOC visit between seven and 14 days after administration of the final dose of study medication and at telephone follow-up at 30 days after the last dose of study medication was administered.

The trial protocol specified the following four patient subsets for evaluation:

·an ITT population consisting of all randomized patients who received at least one dose of study medication;

·an MITT population consisting of all patients in the ITT population who had a documented Gram-positive pathogen culture at baseline;

·a CE population consisting of patients who had a confirmed diagnosis of ABSSSI, received study medication as randomized, received at least 80% of expected study medication, did not receive any potentially concomitant antibiotics, were not unblinded and had a response assessment at the TOC visit; and

·an ME population consisting of patients in the CE population who had a documented Gram-positive pathogen culture at baseline.

The primary efficacy endpoint of the trial was the clinical success rate at the TOC visit for the 100 mg and 150 mg dosage forms of IV lefamulin in both the CE and MITT populations compared to vancomycin. Clinical success was defined as complete resolution or significant improvement of all local and systemic signs and symptoms of infection with no further systemic antibiotic treatment required.

Key secondary efficacy and exploratory endpoints of the trial included the following:

·assessment of clinical response in the ITT and ME populations;

·comparison of clinical response by pathogen and microbiological response by pathogen;

·change in lesion size and resolution of fever; and

·clinical response at day 3.

Evaluation of pharmacokinetic parameters in the trial included analysis of plasma concentrations of lefamulin in blood samples after the first dose on day 1, on day 5 and on the final treatment day.

Three of the 210 patients enrolled in the trial did not receive study medication, resulting in 207 patients in the ITT population. Of the patients in the ITT population, 105 patients had cellulitis (50.7%), 64 patients had abscess with cellulitis (30.9%), 37 patients had wound infections (17.9%) and one patient had burns (0.5%). At least one pathogen responsible for ABSSSI was identified in 155 patients. Of these patients, 152 patients (97.4%) had at least one Gram-positive pathogen, comprising the MITT population. The most frequent Gram-positive pathogen was S. aureus, with the majority, 69.1% of patients in the MITT population, being methicillin-resistant strains. The CE population included 165 patients. The ME population included 129 patients.

Patient demographics were similar across all three treatment groups, except for the presence of diabetes at baseline. The 150 mg lefamulin dose group included a slightly greater proportion of patients with diabetes than the other treatment groups.

In the trial, the patients in the lefamulin treatment groups experienced a similar clinical success rate at the TOC visit as patients in the vancomycin treatment group, in each of the ITT, MITT, CE and ME patient subsets. These results are summarized in the table below. In addition, the clinical success rate in the trial was high for important subgroups of patients based on factors such as primary infection type and diabetes mellitus status. The table below also shows the 95% confidence interval, a statistical determination that demonstrates the range of possible differences in the point estimate of success that will arise 95% of the time that the endpoint is measured. However, this trial was not statistically powered to determine differences between treatment groups. The sample size chosen was to provide clinically meaningful information on efficacy, safety and tolerability. In this table and other tables appearing below, the abbreviation N refers to the number of patients or subjects in each group or subgroup.

In the trial, the patients in the lefamulin treatment groups also experienced a similar clinical response at the day 3 visit as patients in the vancomycin treatment group in each of the ITT, MITT, CE and ME patient subsets. The clinical response results for the ITT patient subset are presented in the table below. Importantly, the assessment at day 3 included evaluation of a new primary endpoint recommended by the FDA of at least a 20% reduction in area of erythema, or redness.

Clinical Response at Day 3 (ITT Population)

Definition of Responder Used

Lefamulin 100 mg (N=70) N (%)

Lefamulin 150 mg (N=71) N (%)

Vancomycin 1,000 mg (N=66) N (%)

Overall clinical response

53 (88.3)

48 (88.9)

44 (86.3)

Absence of fever at Day 3

67 (95.7)

67 (94.4)

61 (92.4)

No increase in area of erythema plus absence of fever

60 (85.7)

59 (83.1)

53 (80.3)

No increase in area of erythema and swelling and absence of fever

53 (75.7)

53 (74.6)

49 (74.2)

>20% reduction in area of erythema

52 (74.3)

50 (70.4)

47 (71.2)

A list of all pathogens identified at baseline along with the corresponding eradication rate by treatment group in the MITT patient subset is presented in the table below. Microbiological eradication rate was defined as the proportion of patients with a microbiological outcome of eradication or presumed eradication based on cultures from both the primary infection site and blood cultures. Patients with indeterminate or missing clinical

responses were considered non-eradication. Overall, in the MITT population, microbiological success was achieved in 40 of 50 patients (80.0%) in the lefamulin 100 mg group, 43 of 51 patients (84.3%) in the lefamulin 150 mg group, and 42 of 51 patients (82.4%) in the vancomycin group. We did not observe development of decreased susceptibility to lefamulin or vancomycin during the trial. In this table, the abbreviation n refers to the number of patients who had a microbiological outcome of eradication or presumed eradication for each specified pathogen.

We evaluated the clinical success of lefamulin against S. aureus, which is the most commonly identified cause of ABSSSI. The clinical success rate against a variety of subsets of S. aureus based on in vitro antibiotic susceptibility (methicillin-resistance), as well as the presence or absence of the virulence factors PVL-positivity or USA300, are clinically important, as limited therapeutic options exist to treat such infection. A summary of the clinical success rate against S. aureus is presented in the table below. The clinical success rates for lefamulin against PVL-positive MRSA and USA300 MRSA strains were similar to, or numerically higher than, the corresponding clinical success rates for vancomycin. In this table, the abbreviation n refers to the number of patients with clinical success for each specified pathogen.

The mean duration of exposure to study medication treatment was approximately seven days for all groups, and almost 70% of patients completed therapy within that time.

Safety and tolerability

Lefamulin was well tolerated in this trial. No patient in the trial suffered any serious adverse events that were found to be related to lefamulin, and no patient in the trial died. The percentage of patients in the trial arms that experienced any treatment emergent adverse event were similar across treatment groups: 71.4% in the lefamulin 100 mg group, 69.0% in the lefamulin 150 mg group and 74.2% in the vancomycin group. Most of the treatment emergent adverse events were mild to moderate in severity. The table below shows the adverse events experienced by patients in the trial that were assessed by the investigator as possibly or probably related to study medication.

Drug-Related Treatment-Emergent Adverse Events by Preferred Term Reported by More Than 2% of Patients in the ITT Population

Adverse Event

Lefamulin 100 mg (N=70) N (%)

Lefamulin 150 mg (N=71) N (%)

Vancomycin 1,000 mg (N=66) N (%)

Headache

5 (7.1)

9 (12.7)

10 (15.2)

Nausea

5 (7.1)

6 (8.5)

10 (15.2)

Infusion site phlebitis

4 (5.7)

2 (2.8)

0 (0.0)

Diarrhea

3 (4.3)

4 (5.6)

4 (6.1)

Vomiting

3 (4.3)

2 (2.8)

3 (4.5)

Alanine aminotransferase increased

2 (2.9)

2 (2.8)

3 (4.5)

Pruritus generalized

2 (2.9)

1 (1.4)

4 (6.1)

Creatine phosphokinase increased

2 (2.9)

1 (1.4)

0 (0.0)

Phlebitis

2 (2.9)

0 (0.0)

0 (0.0)

Vulvovaginal mycotic infection

2 (2.9)

0 (0.0)

0 (0.0)

Abdominal pain

1 (1.4)

2 (2.8)

0 (0.0)

Aspartate aminotransferase increased

1 (1.4)

1 (1.4)

2 (3.0)

Pruritus

0 (0.0)

2 (2.8)

8 (12.1)

Infusion site pain

0 (0.0)

2 (2.8)

0 (0.0)

Tinnitus

0 (0.0)

2 (2.8)

0 (0.0)

Infusion site reaction

0 (0.0)

2 (2.8)

0 (0.0)

Constipation

0 (0.0)

1 (1.4)

3 (4.5)

Insomnia

0 (0.0)

0 (0.0)

2 (3.0)

The incidences of pain, tenderness, itching, erythema, swelling and thrombosis at the infusion site were higher for the lefamulin 100 mg group and the lefamulin 150 mg group than for the vancomycin group. The majority of these local tolerability symptoms were mild in severity. No patient had a severe local tolerability issue of erythema or swelling. No patient had a local tolerability issue of necrosis. When summarized on an infusion basis, the proportions of infusions with local tolerability events were similar for the treatment groups.

Four patients discontinued study medication following a drug-related adverse event: one patient (1.4%) in the lefamulin 100 mg group (events of hyperhidrosis, vomiting and headache), two patients (2.8%) in the lefamulin 150 mg group (infusion site pain in one patient and dyspnea in the other), and one patient (1.5%) in the vancomycin group (drug eruption).

Because the potential for mild effect on ECG measurements was observed in preclinical studies, we have continued to assess this potential in all human clinical trials we have conducted. In the Phase 2 clinical trial, no change in ECG measurements was considered to be of clinical significance, and no drug-related cardiovascular adverse event was reported. Both lefamulin and vancomycin treatment were associated with a small increase in the QT interval. The QT interval is a measure of the hearts electrical cycle, with a lengthened QT interval representing a marker for potential ventricular arrhythmia. We plan to continue to evaluate the effect of lefamulin on the QT interval in our Phase 3 clinical trials of lefamulin for CABP.

The table below summarizes selected pharmacokinetic parameters we obtained from pharmacokinetic sampling in the trial. Cmax refers to the maximum observed peak blood plasma concentration of study medication. AUC refers to the area under the curve in a plot of concentration of study medication in blood plasma over time, representing total drug exposure over time. In this table, the abbreviation SD refers to the standard deviation of the results. Standard deviation is a statistical measure used to quantify the amount of variation within a set of data values. A standard deviation close to zero indicates that the data points do not vary greatly from the mean, while a high standard deviation indicates that the data points are spread over a wider range of values.

Summary Statistics for PK Exposure and Secondary PK Parameters

Dose (mg)

Mean (SD)

Cmax (Day 1)

100

1.57 (0.974)

(µg/mL)

150

1.90 (0.705)

Cmax (Day 5)

100

1.67 (0.974)

(µg/mL)

150

2.06 (0.737)

AUC0-12hr (Day 1)

100

5.14 (2.95)

(µg·hr/mL)

150

6.59 (2.69)

AUC0-12hr (Day 5)

100

6.23 (3.02)

(µg·hr/mL)

150

8.27 (3.11)

Half-life

100

11.0 (5.18)

(hour)

150

13.2 (5.79)

Efficacy for the pleuromutilin class of antibiotics is related to the ratio of total drug exposure over time, measured by the AUC, to minimum inhibitory concentration, or MIC. MIC is the minimum concentration of an antibiotic needed to inhibit growth of an organism. The plasma concentration data obtained from the Phase 2 clinical trial are the first data that describe how lefamulin is absorbed, distributed around the body, metabolized and eliminated in patients suffering from an infection.

Phase 1 Clinical Development

We conducted seventeen Phase 1 clinical trials of lefamulin in Austria, Germany, the United States and the United Kingdom between 2009 and 2015. In these trials, we exposed 321 healthy subjects, including elderly subjects 65 years of age or older, to single or multiple doses of IV or oral lefamulin. The objectives of our Phase 1 clinical trial program have been to understand the absorption and distribution of lefamulin in the blood and target tissues, evaluate the metabolism and elimination route of lefamulin and obtain safety and tolerability data to help predict safe and effective doses of lefamulin for the treatment of patients. We have additional Phase 1 clinical trials ongoing, including drug interaction studies as well as studies in special populations (hepatic and renally impaired subjects).

·no statistically significant effects of age, gender, body weight or height, body mass index or other demographics on the pharmacokinetic parameters of lefamulin;

·the absolute oral bioavailability of a 600 mg immediate release, or IR, tablet formulation of lefamulin were 25.8 % in the fasted and 21% in the fed condition in healthy subjects; and

·in the assessment of relative bioavailability, bioequivalence was demonstrated for the fasted IR tablet and the IV dose, exposure was slightly lower for the fed IR tablet than the IV dose.

Absorption

Lefamulin is absorbed rapidly after oral dosing with or without food. In our Phase 1 clinical trials, steady state blood levels were achieved after two days of dosing every 12 hours, irrespective of the route of administration, and the variability after oral dosing was similar to the variability after IV infusion. Because the ability of pleuromutilin antibiotics to kill bacteria is dependent on the AUC, or total lefamulin exposure over time, to MIC ratio, and IV doses of 150 mg every 12 hours and oral doses of 600 mg every 12 hours achieve similar AUCs, we believe that both regimens are capable of providing a similar therapeutic benefit.

Distribution

Following IV infusion, lefamulin is rapidly distributed throughout the body over approximately 30 minutes. We have observed rapid distribution of lefamulin into tissues, including the skin and ELF of the lung. In CABP, the lung is the target organ where pathogens replicate and cause inflammation that results in mucous production, cough and shortness of breath. Therefore, in 2010, we conducted a Phase 1 clinical trial to assess the pharmacokinetics of lefamulin in 12 healthy subjects. After a single IV administration of 150 mg of lefamulin over 60 minutes, we performed a bronchoalveolar lavage, or BAL, a medical procedure to collect fluid from the lung. We performed BAL analyses in groups of three subjects at 1, 2, 4 and 8 hours after the start of the lefamulin infusion and measured lefamulin concentrations in the ELF, the muscle tissue, soft tissue and blood plasma. In this trial, the exposure of free lefamulin, or the amount of lefamulin not bound to proteins and therefore available to inhibit bacterial growth, achieved in the ELF was approximately six times greater than free lefamulin exposure observed in blood plasma.

Metabolism

The average half-life, or the time it takes the body to eliminate one-half of the concentration of lefamulin present, is 9 to 12 hours. The major route lefamulin is eliminated from the body is the gastrointestinal tract, with limited metabolism of lefamulin occurring mainly through a liver and gut wall enzyme called CYP3A4, which is responsible for the metabolism of a wide variety of medication. We have identified only one metabolite, called BC-8041, as exceeding 10% of lefamulin concentrations in the plasma and only when lefamulin was given orally. None of the metabolites of lefamulin have any antibacterial properties.

Drug Interaction Potential

We continue to perform studies recommended by regulatory authorities to assess the drug-drug interaction potential of new drug products, including the assessment of the impact of potent P-glycoprotein and CYP3A4 inducers on the PK of lefamulin, and the impact of lefamulin on drugs metabolized via CYP3A4.

Safety and Tolerability

Lefamulin has been well tolerated in all Phase 1 trials completed to date. We did not observe any systemic adverse events of clinical concern or any drug-related serious adverse events in these trials. In addition, we did not observe any changes of clinical concern in laboratory safety parameters or vital signs in any subject in any of the trials. The most commonly observed adverse effects with oral administration of lefamulin were related to the gastrointestinal tract, including nausea and abdominal discomfort, while the most commonly observed adverse effects related to IV administration were related to irritation at the infusion site. In addition, lefamulin produced a transient, predictable and reproducible prolongation of the QT interval based on the maximum concentration of the drug in the blood plasma. At therapeutic doses, we expect that the drug will not produce large effects on the QT interval that would be of clinical relevance. We did not observe any drug-related cardiac

adverse events, such as increase in ectopic ventricular activity or other cardiac arrhythmia, or clinically relevant ECG findings during the conduct of any of our Phase 1 or Phase 2 clinical trials.

Intravenous Formulation

We have administered IV lefamulin as single and repeat doses every 12 hours for up to 14 days. The most frequently reported adverse events in our Phase 1 clinical trials were pain or erythema at the site of the IV infusion. To further assess local tolerability, we conducted a Phase 1 clinical trial in 2013 to evaluate the local tolerability of two different IV formulations of lefamulin dosed every twelve hours for 7.5 days. In this trial, we compared lefamulin infusions given in normal saline solution, a sterile sodium chloride solution commonly used to administer IV medications, with lefamulin infusions given in a sterile saline solution buffered by a citrate salt that adjusted the pH, or level of acidity, of the solution. We enrolled 60 healthy subjects in the trial, of which 25 received the normal saline solution, 25 received the citrate buffered solution and ten received a matching placebo solution. Although we did not observe any difference between treatment arms over the first three days of study infusions, over the entire treatment period, the incidence of local pain or redness of at least moderate severity was statistically higher with lefamulin in the saline solution (84%), as compared to the citrate buffered infusions (36%) or placebo (10%). There was no statistical difference between citrate buffered infusions and placebo at any time period during the trial. As a result, we will administer lefamulin IV infusions in a citrate buffered saline solution in our Phase 3 clinical trials for CABP.

Oral Formulation

Initially, we administered lefamulin orally in capsules as single and repeat doses for up to five days. Oral administration of lefamulin was generally well tolerated with infrequent reports of mild gastrointestinal findings, such as nausea, abdominal pain and diarrhea. We subsequently developed 600 mg tablets that we have investigated in single and repeat dose studies. These tablets have been well tolerated and shown favorable pharmacokinetics. We will utilize the 600 mg tablets in our Phase 3 clinical trials.

Electrocardiogram Measurements

In our Phase 1 clinical trials, lefamulin was associated with a Cmax-dependent, transient, predictable, reversible and reproducible prolongation of the QT interval. We have closely monitored ECG measurements in all our trials. We did not observe any drug-related cardiac adverse events, such as increase in ectopic ventricular activity or other cardiac arrhythmia, or clinically relevant ECG findings during the conduct of any of our Phase 1 clinical trials. None of the ECG stopping criteria defined in the trial protocols was reached in any clinical trial. We plan to continue to assess the effects of lefamulin on the QT interval in our planned clinical trials.

Preclinical Development

In our preclinical studies, administration of lefamulin was well tolerated in a variety of animal models. Lefamulin was active against a broad range of bacteria, suggesting possible use as monotherapy for CABP with a low propensity for development of bacterial resistance.

Nonclinical Safety

In several preclinical safety and toxicity studies, including repeat dose toxicity, local tolerance, genotoxicity, development and reproductive toxicity, and safety pharmacology testing in both rodent and non-rodent species, lefamulin was safe and well tolerated. When we treated rats or monkeys for up to four weeks with either oral or IV lefamulin, we did not identify any specific target organ toxicity. Lefamulin was not associated with genetic damage, effects on fertility or birth defects. We are also conducting longer term toxicity studies in a rodent and a non-rodent species.

Antimicrobial Spectrum of Lefamulin

We have extensively studied the antimicrobial in vitro activity of lefamulin against a variety of respiratory, or aerobic, and non-respiratory, or anaerobic, bacterial pathogens representing more than 17,700 clinical isolates collected from patients worldwide. A summary of our observations is presented in the table

below. MIC90 indicates the concentration of drug that inhibits 90% of the pathogens in vitro, while MIC50 indicates the concentration of drug that inhibits 50% of the pathogens in vitro.

Antimicrobial Activity of Lefamulin Against Gram-Positive, Gram-Negative and Atypical Bacteria

MIC [µg/mL]

Organism

N

50%

90%

Aerobic and facultative anaerobic Gram-positive microorganisms

S. aureus

7984

0.12

0.12

S. aureus, MSSA

4365

0.06

0.12

S. aureus, MRSA

3619

0.12

0.25

CA-MRSA (USA 300/400)

50

0.12

0.12

VRSA, VISA, hVISA

30

0.06

0.25

Coagulase-negative Staphylococcus species

1133

0.06

0.12

S. epidermidis

474

0.06

0.25

S. pneumoniae

3570

0.12

0.25

S. pyogenes (Group A Streptococcus species)

472

0.03

0.03

S. agalactiae (Group B Streptococcus species)

503

0.03

0.06

Group C Streptococcus species

116

0.03

0.06

Group G Streptococcus species

160

0.03

0.06

Viridans Group Streptococcus species

445

0.12

0.5

E. faecalis

50

>32

>32

E. faecium

850

0.12

8

E. faecium, VSE

361

0.12

>32

E. faecium, VRE

389

0.06

0.5

Aerobic and facultative anaerobic Gram-negative microorganisms

H. influenzae

1078

0.5

1

L. pneumophila

30

0.12

0.5

M. catarrhalis

855

0.12

0.25

N. gonorrhoeae, resistant isolates

93

0.12

0.5

E. coli

40

16

32

Anaerobic microorganisms

C. difficile

43

4

8

Clostridium species

10

1

>16

Peptostreptococcus species

10

0.06

1

Porphyromonas species

10

0.03

0.03

B. fragilis and B. fragilis group

22

>32

>32

Other microorganisms

C. pneumoniae

50

0.02

0.04

C. trachomatis

15

0.02

0.04

M. pneumoniae

60

<0.001

0.002

The tables below compare the in vitro activity of lefamulin and various antibiotics for CABP and ABSSSI pathogens against various strains of bacteria, including those resistant to current antibiotics. Unlike other CABP antibiotics, such as ß-lactam/ß-lactamase inhibitor combinations, glycopeptides and oxazolidinones, lefamulin was active against the vast majority of potential respiratory pathogens collected in 2015. When an alternative antibiotic from the same drug class was utilized, it is footnoted within the table and below.

Activity Against Resistant Strains and Low Propensity for Development of Bacterial Resistance

When tested against bacterial organisms resistant to macrolides, tetracyclines, quinolones, trimethoprim/sulfamethoxazole, vancomycin, mupirocin or ß-lactams, we did not observe any cross-resistance with lefamulin. Lefamulin displayed activity in vitro against drug-resistant N. gonorrhoeae, VRE, MRSA, multi-drug resistant S. pneumoniae, VISA/hVISA, erythromycin-resistant group A Streptococcus species and clindamycin-resistant group B Streptococcus species, all of which are listed as urgent, serious or concerning threats by the CDC. We utilized the interpretative criteria of the Clinical and Laboratory Standards Institute, or CLSI, to categorize the in vitro activity of each comparator against the organisms listed in the table below as sensitive (%S), intermediate (%I) or resistant (%R). Bold and underlined data indicate resistance according to CLSI criteria.

Lefamulin in vitro Activity Against Resistant Bacterial Pathogens Listed as Urgent, Serious or Concerning Threats According to CDC

(b) No breakpoints by CLSI available; criteria as published by the European Committee on Antimicrobial Susceptibility Testing (2014).

(c) Criteria as published by CLSI (2014).

(d) No breakpoints by CLSI available; criteria as published by the European Committee on Antimicrobial Susceptibility Testing (2011).

(e) Breakpoints of tetracycline applied.

Lefamulin has shown low potential for resistance development in vitro, which we believe is the result of the specific interaction with a binding site on the ribosome. Repeated exposure to low levels of lefamulin in laboratory tests resulted in a slow and step-wise development of resistance in S. aureus, Streptococcus species, and E. faecium. We believe that lefamulins low potential for resistance is further supported by the fact that we observed isolates with consistently low MICs during our Phase 2 clinical trial in ABSSSI and that, despite the use of pleuromutilins in veterinary medicine for decades, the incidence of pleuromutilin-resistant isolates remains relatively low. Cross-resistance between lefamulin and other classes of antibiotics has also been rarely observed in our completed studies to date. Based on global surveillance studies in more than 13,600 clinical isolates, fewer than 0.02% of isolates contain mutations responsible for methylating, or chemically modifying, the interaction between lefamulin and other protein synthesis inhibiting antibiotics. One example of this mutation is called cfr mutation, which when present has resulted in observed elevations in the MIC90 to lefamulin as well as other antibiotics, such as chloramphenicol and linezolid.

Activity in Animals

We evaluated the activity of lefamulin in a number of murine, or mouse, infection models, including pneumonia, septicemia, and thigh infection models. In these models, lefamulin was efficacious against S.

pneumoniae (penicillin- and macrolide-resistant) and S. aureus (methicillin-susceptible, or MSSA, and MRSA). Lefamulin was active against serious lung infections caused by clinically relevant strains of S. pneumoniae or S. aureus. Investigations of the exposure levels in the ELF in the lungs of mice showed rapid distribution of lefamulin into the lung compartment with penetration rates into the ELF of 12-fold compared to free plasma concentration measured in the same mice. We confirmed this result by whole-body imaging using radioactive labeled lefamulin.

Lefamulin also showed high intracellular activity and rapid accumulation in macrophages, or immune cells that are responsible for assisting in clearing bacterial infections from the lung and other body sites, (30- to 50-fold) dependent on the time of incubation and lefamulin concentration. Azithromycin showed a 15- to 20-fold accumulation in the same experiments. Furthermore, the activity of lefamulin was unaffected by lung surfactant, a naturally occurring substance found in the lung that has the ability to inactivate some antibiotics.

Concentrations of Lefamulin Predicted to be Effective in Treating Lung Infections

We believe that results from preclinical analyses of concentrations of lefamulin in lung tissue indicate the potential for favorable outcomes in CABP patients treated with lefamulin. We have provided and discussed with regulatory authorities, including the FDA, these preclinical results and the safety and efficacy of lefamulin observed in subjects and patients with ABSSSI. Based on these discussions, we intend to evaluate the efficacy and safety of lefamulin in our Phase 3 clinical trials for CABP. We used results obtained from pharmacokinetic analyses of lefamulin concentrations over time and pharmacodynamic analyses of the relationship of concentrations of lefamulin and effect, also called PK-PD, to determine the predicted likelihood of achieving lefamulin concentrations in the lung that would be effective at inhibiting the growth of common bacterial causes of CABP. This assessment utilized a population pharmacokinetic model that describes the behavior of lefamulin in blood plasma in subjects and patients with infection, the ELF concentrations achieved in healthy volunteers, in vitro MIC targets for the most common causative pathogens associated with CABP accrued from a robust, global in vitro surveillance library, and mathematical simulations replicating thousands of scenarios that could represent the many possible combinations of lefamulin concentrations achieved and the MIC required to inhibit bacterial growth. Based on these assessments, we believe that a lefamulin regimen of either 150 mg administered by IV every 12 hours or 600 mg administered orally every 12 hours has a probability of 96% or more to achieve concentrations in the ELF that would inhibit the growth of both S. pneumoniae and S. aureus.

Based on all of the available evidence, including lefamulins in vitro activity, clinical pharmacokinetics and tissue penetration, and safety and efficacy observed in our Phase 2 clinical trial for ABSSSI, we are using a dose of 150 mg IV or 600 mg orally every 12 hours in our Phase 3 clinical trials of lefamulin for CABP.

Earlier Stage Product Pipeline

Additional Indications for Lefamulin

ABSSSI

Acute bacterial skin and skin structure infections are common and are characterized by a wide range of disease presentations. Gram-positive bacteria, in particular S. aureus, S. pyogenes and S. agalactiae, are the most common pathogens in ABSSSI. The rising frequency of ABSSSI caused by MRSA and the significant increase in the occurrence of CA-MRSA infections over the past 15 years is an increasing concern. According to IDSA Skin and Skin Structure Infection guidelines 2014, in most U.S. cities, CA-MRSA is now the most common pathogen cultured from patients with ABSSSI in emergency departments. While the current standard of care for MRSA infections is vancomycin, the efficacy of this treatment is being compromised because of decreased susceptibility, or even resistance, of S. aureus to vancomycin. In addition, although linezolid is approved for ABSSSI due to MRSA, its use has been limited because of potential adverse events and drug-drug interactions with commonly prescribed concomitant medications such as antidepressants.

The emerging incidence of resistance to multiple antibiotics in pathogens makes ABSSSI increasingly difficult to treat and results in a need for alternate therapies. Based on our preclinical studies and clinical trials, we believe that lefamulin has potential to treat ABSSSI. In preclinical studies, lefamulin has shown in vitro antibacterial activity against the most relevant pathogens responsible for ABSSSI including S. aureus (MSSA, MRSA, and CA-MRSA), S. pyogenes, and S. agalactiae. In our Phase 2 clinical trial evaluating the safety and efficacy of two different doses of the IV formulation of lefamulin administered over five to 14 days compared to vancomycin in patients with ABSSSI, the clinical success rate at test of cure for lefamulin was similar to that of

vancomycin. We have discussed the design of a proposed Phase 3 clinical trial to evaluate the efficacy and safety of lefamulin for the treatment of ABSSSI with the FDA and several E.U. regulatory authorities.

Pediatric Indications

Not unlike treatment of infectious diseases in adults, the management of pediatric infections has become more difficult due to the continuing rise in resistance in bacteria. Further complicating antimicrobial selection in the pediatric population is the need for agents to be very well tolerated and available in a final dosage form that can be easily administered to children. Based upon the in vitro antimicrobial spectrum of activity, along with the safety profile observed to date, we believe lefamulin is appropriate for evaluation for the treatment of a variety of pediatric infections, including those affecting the respiratory tract and skin and skin structure. We have begun pediatric formulation development activities to support clinical trials in the pediatric population.

HABP/VABP

One of the major causative organisms of hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia is S. aureus, including MRSA. We are evaluating whether to investigate the utility of lefamulin in the treatment of HABP and VABP. We have deferred commencement of a previously planned Phase 1 clinical trial of lefamulin for VABP in order to focus our efforts and our resources on our ongoing Phase 3 clinical trials of lefamulin for CABP.

STIs

Urethritis and cervicitis caused by N. gonorrhoeae, C. trachomatis or M. genitalium are frequently occurring sexually transmitted infections in the United States and Europe. Left untreated, these infections can cause serious health problems, particularly in women, including chronic pelvic pain, life-threatening ectopic pregnancy and infertility. Resistance in these organisms to the most commonly prescribed antibacterial treatments poses a serious public health threat. For example, the CDC estimates that 30% of the clinical isolates of N. gonorrhoeae are resistant to at least one currently available antibiotic.

In preclinical studies, lefamulin has shown high potency against N. gonorrhoeae, C. trachomatis and M. genitalium, including strains resistant to currently available antibacterial agents. As a result, we are actively assessing a non-clinical and clinical development plan to support the development of lefamulin as a first-line treatment for urethritis, cervicitis and pelvic inflammatory disease.

Osteomyelitis

The incidence of osteomyelitis, which is an infection of the bone, is increasing. The most common causative organism is S. aureus. In the United States, the prevalence of MRSA in these cases ranges from 33% to 55%. Up to 90% of cases of hematogenous osteomyelitis, most frequently in children, are caused by S. aureus. We believe that lefamulin has the potential to be an effective treatment option for osteomyelitis. Lefamulin has shown substantial tissue penetration and activity against the most common causative organism in all forms of osteomyelitis. We believe that based on the safety profile observed to date, lefamulin will be well tolerated for the long term use necessary for the treatment of both adult and pediatric patients with osteomyelitis. The current standard of care for these infections is treatment with vancomycin. We believe the ability to administer lefamulin by either the IV or oral route would provide a significant advantage over agents, such as vancomycin, that can only be administered by IV.

Prosthetic Joint Infections

Infection occurs in approximately 1% of joint replacement surgeries. Although the incidence of infection has been decreasing, the total number of replacement operations has been rising, such that, overall, there is increasing morbidity. The majority of these infections are caused by three organisms: coagulase negative staphylococci, S. aureus (including MRSA) and streptococci, all organisms that are sensitive to lefamulin. The preferred treatment for joint infections with MRSA is vancomycin, with daptomycin and linezolid as alternatives. Vancomycin and daptomycin are administered only by IV for this indication, and linezolid has side effects that affect long term use. We believe that lefamulin could provide an alternative for both IV and oral therapy for these infections cases.

BC-7013 is a semi-synthetic compound derived from pleuromutilin with the potential to be developed for the topical treatment of Gram-postivie infections, including uSSSIs.

BC-7013 is highly active against key bacterial pathogens causing skin and ocular infections. The MIC90 values for BC-7013 against MRSA are up to 20-fold lower than for mupirocin and 8-fold lower than for retapamulin, an FDA-approved topical pleuromutilin. Furthermore, BC-7013 has demonstrated potent activity against Chlamydia trachomatis, the leading cause of blindness in the world, and Propionibacterium acnes, the causative agent of acne.

We observed activity in a superficial skin infection model in mice infected with MRSA. BC-7013 was well tolerated following intranasal administration of an ointment formulation in a Phase 1 clinical trial.

Pleuromutilin Molecule Platform

Our pleuromutilin research program is based on our large and diverse proprietary compound library. We believe that our expertise in the areas of medicinal chemistry, pharmacology and toxicology have enabled targeted discovery of novel pleuromutilins through modification of side chains and core positions in the mutilin moiety. These modifications have resulted in alterations in microbial activity, ADME and toxicity of the semi-synthetic molecules.

We are actively pursuing an in-house discovery program to sustain our pipeline with future product candidates. The aim of this program is the development of novel pleuromutilins with enhanced affinity for the bacterial ribosome directed at increasing the antimicrobial potency and broadening the spectrum of activity to include rare strains with known mechanisms of resistance to the pleuromutilin class (e.g. cfr or Vga mutants). We believe next generation pleuromutlins have the potential to exhibit improved antibacterial activity and a pharmacokinetic profile that may make them well suited for the treatment of respiratory tract infections, acute/complicated bacterial skin infections, sexually transmitted infections and biothreat organisms.

Compounds in Other Antibiotic Classes

In addition to the pleuromutilin research program, we own a ß-lactam library encompassing approximately 2,000 novel broad spectrum cephalosporins and approximately 150 novel ß-lactamase inhibitor molecules. We own all rights and hold one active patent application on file covering ß-lactamase inhibitors.

We also own a library of approximately 200 acremonic acid derivatives which inhibit bacterial protein translation and have an antibacterial profile that covers primarily Gram-positive bacteria, such as S. aureus, MRSA and mupirocin-resistant strains, as well as ß-hemolytic streptococci (Streptococci that are not S. pneumoniae or members of the Viridans family). The first molecules in this series also displayed improved activity against isolates showing resistance against fusidic acid and showed no cross-resistance with other classes of antibiotics tested.

The existing compound libraries of ß-lactam/ß-lactamase inhibitors and acremonic acid derivatives represent an unrecognized portion of our pipeline. The current allocation of our funds and staff are dedicated to advancing the pleuromutilin compounds. Assessment of the ß-lactam/ß-lactamase inhibitors and acremonic acid derivatives compound libraries will be dependent upon additional funding.

Commercialization Strategy

We own exclusive, worldwide rights to lefamulin. We expect that our initial target population for lefamulin will consist of patients with moderate to severe CABP whose antibiotic treatment is hospital-initiated. If lefamulin receives marketing approval from the FDA for the treatment of CABP, we plan to pursue commercialization strategies that maximize the value of lefamulin in the United States with our own targeted hospital sales and marketing organization that we plan to establish. We believe that we will be able to effectively communicate lefamulins differentiating characteristics, positioning and key attributes to clinicians, hospital pharmacists and managed care organizations, with the goal of establishing favorable formulary status

for lefamulin. Based on our market research, we believe lefamulin has a novel position supporting adoption in the United States for adult CABP hospital-initated treatments, which we believe represents a significant commercial opportunity. Additionally, we believe that our plans for a targeted hospital-focused sales force should allow us to address on our own the hospital-initiated treatment market for CABP in the United States. We plan to continue our pre-commercialization activities to prepare for a potential commercial launch of lefamulin, subject to marketing approval in the United States. If lefamulin receives marketing approval outside of the United States for the treatment of CABP, we expect to utilize a variety of types of collaboration, distribution and other marketing arrangements with one or more third parties to commercialize lefamulin in such markets.

Along with additional market research, we believe that medical education will be a key component of our commercialization efforts and, following potential commercial launch, plan to invest in these activities to maximize the commercial potential of lefamulin. With a targeted initial prescribing base predominantly in the hospital setting, we expect that a targeted hospital sales and marketing organization would be relatively smaller than competitors who are focused on both the hospital and community prescribing base. We believe that lefamulins novel mechanism of action, status as the only member of a new class of systemically administered pleuromutilins and anticipated clinical profile will support its potential inclusion on formularies and in local and national treatment guidelines, subject to and following marketing approval.

We plan to evaluate the merits of entering into collaboration agreements with other pharmaceutical or biotechnology companies that may contribute to our ability to efficiently advance our product candidates, build our product pipeline and concurrently advance a range of research and development programs for a variety of indications outside the United States.

Manufacturing

We do not own or operate, and currently have no plans to establish, manufacturing facilities for the production of clinical or commercial quantities of lefamulin, or any of the other compounds that we are evaluating in our discovery program. We currently rely, and expect to continue to rely, on third parties for the manufacture of lefamulin and any further products that we may develop. We have significant in-house knowledge and experience in the relevant chemistry associated with our drug candidate and use these internal resources, alongside third-party consultants, to manage our manufacturing contractors.

We have engaged a limited number of third-party manufacturers to provide all of our raw materials, drug substance and finished product for use in clinical trials. The active pharmaceutical ingredients, or API, and drug products have been produced under master service contracts and specific work orders from these manufacturers pursuant to agreements that include specific supply timelines and volume and quality expectations. We choose the third-party manufacturers of the drug substance based on the volume required and the regulatory requirements at the relevant stage of development. All lots of drug substance and drug products used in clinical trials are manufactured under current good manufacturing practices. Separate third-party manufacturers have been responsible for fill and finish services, and for labeling and shipment of the final drug product to the clinical trial sites.

We do not currently have long-term agreements with any of these third parties. We also do not have any current contractual relationships for the manufacture of commercial supplies of lefamulin if it receives marketing approval. We intend to enter into agreements with suitable third-party contract manufacturers for the commercial production of this product pending potential regulatory approval.

Our product candidate is a semi-synthetic organic compound of low molecular weight. The pleuromutilin core of the molecule is produced by fermentation and is manufactured on a significant scale by various manufacturers. We have selected the compound based on efficacy and safety, although it is also associated with reasonable cost of goods, ready availability of starting materials and ease of synthesis. The production of lefamulin has been carried out at a significant scale and we believe the synthetic route to lefamulin is amenable to further scale-up. The synthetic route does not require unusual, or specialized, equipment in the manufacturing process. Therefore, if any of the future drug substance manufacturers were to become unavailable for any reason, we believe there are a number of potential replacements, although delays may be incurred in identifying and qualifying such replacements.

The biotechnology and pharmaceutical industries are characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. While we believe that our technologies, knowledge, experience and scientific resources provide us with competitive advantages, we face potential competition from many different sources, including major pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions, government agencies and private and public research institutions. Any product candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future.

Many of our competitors may have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs. Smaller or early stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies.

Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any products that we may develop. Our competitors also may obtain marketing approvals for their products more rapidly than we obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market. In addition, our ability to compete may be affected because in some cases insurers or other third-party payors seek to encourage the use of generic products. This may have the effect of making branded products less attractive, from a cost perspective, to buyers. We expect that if lefamulin is approved for CABP, it will be priced at a significant premium over competitive generic products. This may make it difficult for us to replace existing therapies with lefamulin.

The key competitive factors affecting the success of our product candidates are likely to be their efficacy, safety, convenience, price and the availability of coverage and reimbursement from government and other third-party payors.

Currently, the treatment of CABP is dominated by generic products. For hospitalized patients, combination therapy is frequently used. Many currently approved drugs are well established therapies and are widely used by physicians, patients and third-party payors. We also are aware of various drugs under development for the treatment of CABP, including solithromycin (NDA filed by Cempra Inc. and complete response letter issued by the FDA in December 2016), omadacycline (under Phase 3 clinical development by Paratek Pharmaceuticals Inc.) and delafloxacin (under Phase 3 clinical development by Melinta Therapeutics Inc.).

Intellectual Property

Our success depends in large part on our ability to obtain and maintain proprietary protection for our product candidates, technology and know-how, to operate without infringing the proprietary rights of others and to prevent others from infringing our proprietary rights. We strive to protect the proprietary technology that we believe is important to our business by, among other methods, seeking and maintaining patents, where available, that are intended to cover our product candidates, compositions and formulations, their methods of use and processes for their manufacture and any other inventions that are commercially important to the development of our business. We also rely on trade secrets, know-how, continuing technological innovation and in-licensing opportunities to develop and maintain our proprietary and competitive position.

As of February 10, 2017, we owned 21 different families of patents and patent applications, including 20 families directed to the various pleuromutilin derivatives as compositions of matter, processes for their manufacture, and their use in pharmaceutical compositions and methods of treating disease. The remaining family is directed to ß-lactamase inhibitors. Our patent portfolio includes 22 issued U.S. patents, 20 granted European patents and 16 granted Japanese patents, as well as patents in other jurisdictions. We also have pending patent applications in the United States, Europe, Japan and other countries and regions, including Asia,

All of these patents and patent applications are assigned solely to us and were either originally filed by us or originally filed by Sandoz and subsequently assigned to us.

As of February 10, 2017, our lead product candidate, lefamulin, was protected by the following six patent families:

·The first patent family includes patents and applications with claims directed to generic classes of compounds that include lefamulin and/or their use in the treatment of microbial infections. This family includes issued patents in the United States, Europe and Japan, as well as issued patents in 10 other jurisdictions. The standard term for patents in this family expires in 2021.

·The second patent family includes patents and applications with claims that specifically recite lefamulin and/or its use in the treatment of microbial infections. This family includes two issued patents in each of the United States, Europe and Japan, as well as issued patents in 19 other jurisdictions and 8 pending patent applications in other jurisdictions, including one divisional application in the United States. The standard term for patents in this family expires in 2028. A patent term adjustment of 303 days has already been obtained in the United States for one patent.

·The third patent family includes patents and applications with claims directed to the processes for the manufacture of lefamulin, crystalline intermediates useful in the processes, and the resulting crystalline salts. This family includes 11 granted patents and pending patent applications in Europe and 16 other jurisdictions. The standard term for patents in this family expires in 2031.

·The fourth patent family includes patents and applications with claims directed to processes for the synthetic manufacture of crystalline intermediates useful in the manufacture of lefamulin. This family includes granted patents in Europe and the United States and granted patents in other jurisdictions and further pending applications. The standard term for patents in this family expires in 2031.

·The fifth patent family includes patents and applications with claims directed to pharmaceuticals and treatments for Helicobacter infection, including pleuromutilins, such as lefamulin. This family includes issued patents in the United States, Europe and one other jurisdiction. The standard term for patents in this family expires in 2023. A patent term adjustment of 921 days has already been obtained for the U.S. patent.

·A further patent family is directed to pharmaceutical compositions of lefamulin and the PCT-application was recently published.

Our second most advanced product candidate, BC-7013, is covered specifically in one patent family with patents granted in the United States, Europe and Japan, as well as eight other jurisdictions, and pending patent applications in other jurisdictions. The standard term for patents in this family expires in 2027.

The remaining 13 pleuromutilin patent families are directed to either molecules in the intellectual property landscape surrounding our product candidates in development or molecules which can be potentially further developed by us but have not yet been pursued. All patent applications in these families have been filed at least in the United States and Europe, and most have been filed in other countries. The majority of these patent applications have already resulted in granted patents.

Finally, we own one patent family directed to ß-lactamase inhibitor compounds. Patent applications in this family have been filed and granted in the United States and Europe. The standard term for patents in this family expires in 2030.

The term of individual patents depends upon the legal term for patents in the countries in which they are obtained. In most countries, including the United States, the patent term is 20 years from the filing date of a non-provisional patent application. In the United States, a patents term may, in certain cases, be lengthened by

patent term adjustment, which compensates a patentee for administrative delays by the U.S. Patent and Trademark Office, or the USPTO, in examining and granting a patent, or may be shortened if a patent is terminally disclaimed over an earlier filed patent. The term of a U.S. patent that covers a drug, biological product or medical device approved pursuant to a pre-market approval, or PMA, may also be eligible for patent term extension when FDA approval is granted, provided that certain statutory and regulatory requirements are met. The length of the patent term extension is related to the length of time the drug is under regulatory review while the patent is in force. The Drug Price Competition and Patent Term Restoration Act of 1984, or the Hatch-Waxman Act, permits a patent term extension of up to five years beyond the expiration date set for the patent. Patent extension cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval, only one patent applicable to each regulatory review period may be granted an extension and only those claims reading on the approved drug may be extended. Similar provisions are available in Europe and certain other foreign jurisdictions to extend the term of a patent that covers an approved drug, provided that statutory and regulatory requirements are met. Thus, in the future, if and when our product candidates receive approval by the FDA or foreign regulatory authorities, we expect to apply for patent term extensions on issued patents covering those products, depending upon the length of the clinical trials for each drug and other factors. The expiration dates of our patents and patent applications referred to above are without regard to potential patent term extension or other market exclusivity that may be available to us.

In addition to patents, we may rely, in some circumstances, on trade secrets to protect our technology and maintain our competitive position. However, trade secrets can be difficult to protect. We seek to protect our proprietary technology and processes, in part, by confidentiality agreements with our employees, corporate and scientific collaborators, consultants, scientific advisors, contractors and other third parties. We also seek to preserve the integrity and confidentiality of our data and trade secrets by maintaining physical security of our premises and physical and electronic security of our information technology systems.

Government Regulation

Government authorities in the United States, at the federal, state and local level, and in other countries and jurisdictions, including the European Union, extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, and import and export of pharmaceutical products. The processes for obtaining regulatory approvals in the United States and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

Review and Approval of Drugs in the United States

In the United States, the FDA reviews, approves and regulates drugs under the federal Food, Drug, and Cosmetic Act, or FDCA, and associated implementing regulations. The failure to comply with the applicable U.S. requirements at any time during the product development process, approval process or after approval may subject an applicant and/or sponsor to a variety of administrative or judicial sanctions, including refusal by the FDA to approve pending applications, withdrawal of an approval, imposition of a clinical hold, issuance of warning letters and other types of letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement of profits, or civil or criminal investigations and penalties brought by the FDA and the U.S. Department of Justice, or DOJ, or other governmental entities.

An applicant seeking approval to market and distribute a new drug product in the United States must typically undertake the following:

·completion of preclinical laboratory tests, animal studies and formulation studies in compliance with the FDAs good laboratory practice, or GLP, regulations;

·submission to the FDA of an investigational new drug application, or IND, which must take effect before human clinical trials may begin;

·approval by an independent institutional review board, or IRB, representing each clinical site before each clinical trial may be initiated;

·performance of adequate and well-controlled human clinical trials in accordance with good clinical practices, or GCP, to establish the safety and efficacy of the proposed drug product for each indication;

·preparation and submission to the FDA of a new drug application, or NDA, summarizing available data to support the proposed approval of the new drug product for the proposed use;

·review of the product application by an FDA advisory committee, where appropriate or if applicable and as may be requested by the FDA;

·satisfactory completion of one or more FDA inspections of the manufacturing facility or facilities at which the product, or components thereof, are produced to assess compliance with current Good Manufacturing Practices, or cGMP, requirements and to assure that the facilities, methods and controls are adequate to preserve the products identity, strength, quality and purity;

·satisfactory completion of FDA audits of clinical trial sites to assure compliance with GCPs and the integrity of the clinical data;

·payment of user fees (per published PDUFA guidelines for the applicable year) and securing FDA approval of the NDA; and

·compliance with any post-approval requirements, including the potential requirement to implement a Risk Evaluation and Mitigation Strategy, or REMS, where applicable, and the potential to conduct post-approval studies required by the FDA.

Preclinical Studies

Before an applicant begins testing a compound with potential therapeutic value in humans, the drug candidate enters the preclinical testing stage. Preclinical studies include laboratory evaluation of the purity and stability of the manufactured drug substance or active pharmaceutical ingredient and the formulated drug or drug product, as well as in vitro and animal studies to assess the safety and activity of the drug for initial testing in humans and to establish a rationale for therapeutic use. The conduct of preclinical studies is subject to federal regulations and requirements, including GLP regulations. The results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical studies, among other things, are submitted to the FDA as part of an IND. Additional long-term preclinical testing, such as animal tests of reproductive adverse events and carcinogenicity, may continue after the IND is submitted.

Companies usually must complete some long-term preclinical testing, such as animal tests of long term exposure and reproductive adverse events, and must also develop additional information about the chemistry and physical characteristics of the investigational product and finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the candidate product and, among other things, the manufacturer must develop methods for testing the identity, strength, quality and purity of the final product. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the candidate product does not undergo unacceptable deterioration over its shelf life.

The IND and IRB Processes

An IND is an exemption from the FDCA that allows an unapproved drug to be shipped in interstate commerce for use in an investigational clinical trial and a request for FDA authorization to administer an investigational drug to humans. Such authorization must be secured prior to interstate shipment and administration of any new drug that is not the subject of an approved NDA. In support of a request for an IND, applicants must submit a protocol for each clinical trial and any subsequent protocol amendments must be submitted to the FDA as part of the IND. In addition, the results of the preclinical tests, together with manufacturing information, analytical data, any available clinical data or literature and plans for clinical trials, among other things, are submitted to the FDA as part of an IND. The FDA requires a 30-day waiting period after the filing of each IND before clinical trials may begin. This waiting period is designed to allow the FDA to review the IND to determine whether human research subjects will be exposed to unreasonable health risks. At any time during this 30-day period, the FDA may raise concerns or questions about the conduct of the trials as outlined in the IND and impose a clinical hold. In this case, the IND sponsor and the FDA must resolve any

Following commencement of a clinical trial under an IND, the FDA may also place a clinical hold or partial clinical hold on that trial. A clinical hold is an order issued by the FDA to the sponsor to delay a proposed clinical investigation or to suspend an ongoing investigation. A partial clinical hold is a delay or suspension of only part of the clinical work requested under the IND. For example, a specific protocol or part of a protocol is not allowed to proceed, while other protocols may do so. No more than 30 days after imposition of a clinical hold or partial clinical hold, the FDA will provide the sponsor a written explanation of the basis for the hold. Following issuance of a clinical hold or partial clinical hold, an investigation may only resume after the FDA has notified the sponsor that the investigation may proceed. The FDA will base that determination on information provided by the sponsor correcting the deficiencies previously cited or otherwise satisfying the FDA that the investigation can proceed.

A sponsor may choose, but is not required, to conduct a foreign clinical study under an IND. When a foreign clinical study is conducted under an IND, all FDA IND requirements must be met unless waived. When the foreign clinical study is not conducted under an IND, the sponsor must ensure that the study complies with FDA certain regulatory requirements in order to use the study as support for an IND or application for marketing approval. Specifically, on April 28, 2008, the FDA amended its regulations governing the acceptance of foreign clinical studies not conducted under an investigational new drug application as support for an IND or a new drug application. The final rule provides that such studies must be conducted in accordance with good clinical practice, or GCP, including review and approval by an independent ethics committee, or IEC, and informed consent from subjects. The GCP requirements in the final rule encompass both ethical and data integrity standards for clinical studies. The FDAs regulations are intended to help ensure the protection of human subjects enrolled in non-IND foreign clinical studies, as well as the quality and integrity of the resulting data. They further help ensure that non-IND foreign studies are conducted in a manner comparable to that required for IND studies.

In addition to the foregoing IND requirements, an IRB representing each institution participating in the clinical trial must review and approve the plan for any clinical trial before it commences at that institution, and the IRB must conduct continuing review and reapprove the study at least annually. The IRB must review and approve, among other things, the study protocol and informed consent information to be provided to study subjects. An IRB must operate in compliance with FDA regulations. An IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRBs requirements or if the product candidate has been associated with unexpected serious harm to patients.

Additionally, some trials are overseen by an independent group of qualified experts organized by the trial sponsor, known as a data safety monitoring board or committee. This group provides recommendations on whether or not a trial should move forward at designated check points based on unblinded safety data from the study that only the group has access to.. Suspension or termination of development during any phase of clinical trials may occur if it is determined that the participants or patients are being exposed to an unacceptable health risk. Other reasons for suspension or termination may be made by us based on evolving business objectives and/or competitive climate.

Information about certain clinical trials must be submitted within specific timeframes to the National Institutes of Health, or NIH, for public dissemination on its ClinicalTrials.gov website.

Human Clinical Studies in Support of an NDA

Clinical trials involve the administration of the investigational product to human subjects under the supervision of qualified investigators in accordance with GCP requirements, which include, among other things, the requirement that all research subjects provide their informed consent in writing before their participation in any clinical trial. Clinical trials are conducted under written study protocols detailing, among other things, the inclusion and exclusion criteria, the objectives of the study, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated.

Human clinical trials are typically conducted in the following sequential phases, which may overlap or be combined:

·Phase 1: The drug is initially introduced into healthy human subjects or, in certain indications such

as cancer, patients with the target disease or condition and tested for safety, dosage tolerance, absorption, metabolism, distribution, excretion and, if possible, to gain an early indication of its effectiveness and to determine optimal dosage.

·Phase 2: The drug is administered to a limited patient population to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy of the product for specific targeted diseases and to determine dosage tolerance and optimal dosage.

·Phase 3: The drug is administered to an expanded patient population, generally at geographically dispersed clinical trial sites, in well-controlled clinical trials to generate enough data to statistically evaluate the efficacy and safety of the product for approval, to establish the overall risk-benefit profile of the product, and to provide adequate information for the labeling of the product.

·Phase 4: Post-approval studies, which are conducted following initial approval, are typically conducted to gain additional experience and data from treatment of patients in the intended therapeutic indication.

Progress reports detailing the results of the clinical trials must be submitted at least annually to the FDA and more frequently if serious adverse events occur. In addition, IND safety reports must be submitted to the FDA for any of the following: serious and unexpected suspected adverse reactions; findings from other studies or animal or in vitro testing that suggest a significant risk in humans exposed to the drug; and any clinically important increase in the case of a serious suspected adverse reaction over that listed in the protocol or investigator brochure. Phase 1, Phase 2 and Phase 3 clinical trials may not be completed successfully within any specified period, or at all. Furthermore, the FDA or the sponsor may suspend or terminate a clinical trial at any time on various grounds, including a finding that the research subjects are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution, or an institution it represents, if the clinical trial is not being conducted in accordance with the IRBs requirements or if the drug has been associated with unexpected serious harm to patients. The FDA will typically inspect one or more clinical sites to assure compliance with GCP and the integrity of the clinical data submitted.

Concurrent with clinical trials, companies often complete additional animal studies and must also develop additional information about the chemistry and physical characteristics of the drug as well as finalize a process for manufacturing the product in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the drug candidate and, among other things, must develop methods for testing the identity, strength, quality, purity, and potency of the final drug. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the drug candidate does not undergo unacceptable deterioration over its shelf life.

Special Protocol Assessment Agreements

A Special Protocol Assessment, or SPA, agreement is an agreement between a drug manufacturer and the FDA on the design and size of studies and clinical trials that can be used for approval of a drug or biological product. The FDAs guidance on such agreements states that an agreement may not be changed by the manufacturer or the agency unless through a written agreement of the two entities or if FDA determines a substantial scientific issue essential to determining the safety or effectiveness of the drug. The protocols that are eligible for SPA agreements are: animal carcinogenicity protocols, final product stability protocols and clinical protocols for Phase 3 trials whose data will form the primary basis for an efficacy claim.

Specifically, under the FDCA, the FDA may meet with sponsors, provided certain conditions are met, for the purpose of reaching a SPA agreement on the design and size of clinical trials intended to form the primary basis of an efficacy claim in a marketing application. If a sponsor makes a reasonable written request to meet with the FDA for the purpose of reaching agreement on the design and size of a clinical trial, then the FDA will meet with the sponsor. If an agreement is reached, the FDA will reduce the agreement to writing and make it part of the administrative record. An agreement may not be changed by the sponsor or FDA after the trial begins, except with the written agreement of the sponsor and FDA, or if the director of the FDA reviewing division determines that a substantial scientific issue essential to determining the safety or effectiveness of the drug was identified after the testing began. If a sponsor and the FDA meet regarding the design and size of a clinical trial and the parties cannot agree that the trial design is adequate to meet the goals of the sponsor, the FDA will clearly state the reasons for the disagreement in a letter to the sponsor. We reached agreement with

the FDA in September 2015 on a SPA regarding the study design of our first Phase 3 clinical trial of lefamulin for the treatment of CABP.

Submission of an NDA to the FDA

Assuming successful completion of required clinical testing and other requirements, the results of the preclinical and clinical studies, together with detailed information relating to the products chemistry, manufacture, controls and proposed labeling, among other things, are submitted to the FDA as part of an NDA requesting approval to market the drug product for one or more indications. Under federal law, the submission of most NDAs is additionally subject to an application user fee, which for federal fiscal year 2017 is $2,038,100, and the sponsor of an approved NDA is also subject to annual product and establishment user fees, which for fiscal year 2017 are $97,750 per product and $512,000 per establishment Exceptions or waivers for user fees exist for a small company (fewer than 500 employees, including employees and affiliates) satisfying certain requirements and products with orphan drug designation for a particular indication are not subject to an application user fee provided there are no other intended uses in the NDA. We believe that we will not be subject to an application user fee.

Following submission of an NDA, the FDA conducts a preliminary review of an NDA generally within 60 calendar days of its receipt and strives to inform the sponsor by the 74th day after the FDAs receipt of the submission whether the application is sufficiently complete to permit substantive review. The FDA may request additional information rather than accept an NDA for filing. In this event, the application must be resubmitted with the additional information. The resubmitted application is also subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review. The FDA has agreed to certain performance goals in the review process of NDAs. Standard review, representing most such applications are meant to be reviewed within ten months from the date of filing. Priority review applications are meant to be reviewed within six months of filing. The review process may be extended by the FDA for three additional months to consider new information or clarification provided by the applicant to address an outstanding deficiency identified by the FDA following the original submission.

Before approving an NDA, the FDA typically will inspect the facility or facilities where the product is or will be manufactured. These pre-approval inspections may cover all facilities associated with an NDA submission, including drug component manufacturing (such as active pharmaceutical ingredients), finished drug product manufacturing, and control testing laboratories. The FDA will not approve an application unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving an NDA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP.

In addition, as a condition of approval, the FDA may require an applicant to develop a REMS. REMS use risk minimization strategies beyond the professional labeling to ensure that the benefits of the product outweigh the potential risks. To determine whether a REMS is needed, the FDA will consider the size of the population likely to use the product, seriousness of the disease, expected benefit of the product, expected duration of treatment, seriousness of known or potential adverse events, and whether the product is a new molecular entity. REMS can include medication guides, physician communication plans for healthcare professionals, and elements to assure safe use, or ETASU. ETASU may include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring, and the use of patient registries. The FDA may require a REMS before approval or post-approval if it becomes aware of a serious risk associated with use of the product. The requirement for a REMS can materially affect the potential market and profitability of a product.

The FDA may refer an application for a novel drug to an advisory committee or explain why such referral was not made. Typically, an advisory committee is a panel of independent experts, including clinicians and other scientific experts, that reviews, evaluates and provides a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions relating to approval of a new drug product.

an unmet medical need in the treatment of a serious or life-threatening disease or condition. These programs are referred to as fast track designation, breakthrough therapy designation, priority review designation and regenerative advanced therapy designation.

Specifically, the FDA may designate a product for Fast Track review if it is intended, whether alone or in combination with one or more other products, for the treatment of a serious or life-threatening disease or condition, and it demonstrates the potential to address unmet medical needs for such a disease or condition. For Fast Track products, sponsors may have greater interactions with the FDA and the FDA may initiate review of sections of a Fast Track products application before the application is complete. This rolling review may be available if the FDA determines, after preliminary evaluation of clinical data submitted by the sponsor, that a Fast Track product may be effective. The sponsor must also provide, and the FDA must approve, a schedule for the submission of the remaining information and the sponsor must pay applicable user fees. However, the FDAs time period goal for reviewing a Fast Track application does not begin until the last section of the application is submitted. In addition, the Fast Track designation may be withdrawn by the FDA if the FDA believes that the designation is no longer supported by data emerging in the clinical trial process.

Second, a product may be designated as a Breakthrough Therapy if it is intended, either alone or in combination with one or more other products, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The FDA may take certain actions with respect to Breakthrough Therapies, including holding meetings with the sponsor throughout the development process; providing timely advice to the product sponsor regarding development and approval; involving more senior staff in the review process; assigning a cross-disciplinary project lead for the review team; and taking other steps to design the clinical trials in an efficient manner.

Third, the FDA may designate a product for priority review if it is a product that treats a serious condition and, if approved, would provide a significant improvement in safety or effectiveness. The FDA determines, on a case- by-case basis, whether the proposed product represents a significant improvement when compared with other available therapies. Significant improvement may be illustrated by evidence of increased effectiveness in the treatment of a condition, elimination or substantial reduction of a treatment-limiting product reaction, documented enhancement of patient compliance that may lead to improvement in serious outcomes, and evidence of safety and effectiveness in a new subpopulation. A priority designation is intended to direct overall attention and resources to the evaluation of such applications, and to shorten the FDAs goal for taking action on a marketing application from ten months to six months.

Fast Track, Breakthrough Therapy and Priority Review Designations

Accelerated Approval Pathway

The FDA may grant accelerated approval to a drug for a serious or life-threatening condition that provides meaningful therapeutic advantage to patients over existing treatments based upon a determination that the drug has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit. The FDA may also grant accelerated approval for such a drug when the product has an effect on an intermediate clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality, or IMM, and that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. Drugs granted accelerated approval must meet the same statutory standards for safety and effectiveness as those granted traditional approval.

For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. Surrogate endpoints can often be measured more easily or more rapidly than clinical endpoints. An intermediate clinical endpoint is a measurement of a therapeutic effect that is considered reasonably likely to predict the clinical benefit of a drug, such as an effect on IMM. The FDA has limited experience with accelerated approvals based on intermediate clinical endpoints, but has indicated that such endpoints generally may support accelerated approval where the therapeutic effect measured by the endpoint is not itself a clinical benefit and basis for traditional approval, if there is a basis for concluding that the therapeutic effect is reasonably likely to predict the ultimate clinical benefit of a drug.

The accelerated approval pathway is most often used in settings in which the course of a disease is long and an extended period of time is required to measure the intended clinical benefit of a drug, even if the effect on the surrogate or intermediate clinical endpoint occurs rapidly. Thus, accelerated approval has been used extensively in the development and approval of drugs for treatment of a variety of cancers in which the goal of therapy is generally to improve survival or decrease morbidity and the duration of the typical disease course requires lengthy and sometimes large trials to demonstrate a clinical or survival benefit. The accelerated approval pathway is usually contingent on a sponsors agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the drugs clinical benefit. As a result, a drug candidate approved on this basis is subject to rigorous post-marketing compliance requirements, including the completion of Phase 4 or post-approval clinical trials to confirm the effect on the clinical endpoint. Failure to conduct required post-approval studies, or confirm a clinical benefit during post-marketing studies, would allow the FDA to withdraw the drug from the market on an expedited basis. All promotional materials for drug candidates approved under accelerated regulations are subject to prior review by the FDA.

Limited Population Antibacterial Drug Pathway

With passage of the CURES Act, Congress authorized FDA to approve an antibacterial or antifungal drug, alone or in combination with one or more other drugs, as a limited population drug. To qualify for this approval pathway, the drug must be intended to treat a serious or life-threatening infection in a limited population of patients with unmet needs; the standards for approval of drugs and biologics under the FDCA and PHSA must be satisfied; and FDA must receive a written request from the sponsor to approve the drug as a limited population drug pursuant to this provision. The FDAs determination of safety and effectiveness for such a product must reflect the benefit-risk profile of such drug in the intended limited population, taking into account the severity, rarity, or prevalence of the infection the drug is intended to treat and the availability or lack of alternative treatment in such a limited population.

Any drug or biologic approved under this pathway must be labeled with the statement Limited Population in a prominent manner and adjacent to the proprietary name of the drug or biological product. The prescribing information must also state that the drug is indicated for use in a limited and specific population of patients and copies of all promotional materials relating to the drug must be submitted to FDA at least 30 days prior to dissemination of the materials. If FDA subsequently approves the drug for a broader indication, the agency may remove any post-marketing conditions, including requirements with respect to labeling and review of promotional materials applicable to the product. Nothing in this pathway to approval of a limited population drug prevents sponsors of such products from seeking designation or approval under other provisions of the FDCA, such as accelerated approval.

The FDAs Decision on an NDA

On the basis of the FDAs evaluation of the NDA and accompanying information, including the results of the inspection of the manufacturing facilities, the FDA may issue an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A complete response letter generally outlines the deficiencies in the submission and may require additional, sometimes substantial, testing or information in order for the FDA to reconsider the application. If and when those deficiencies have been addressed to the FDAs satisfaction in a resubmission of the NDA, the FDA will issue an approval letter. The FDA has committed to reviewing such resubmissions in two or six months depending on the type of information included. Even with submission of this additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

If the FDA approves a product, it may limit the approved indications for use for the product, require that contraindications, warnings or precautions be included in the product labeling, require that post-approval studies, including Phase 4 clinical trials, be conducted to further assess the drugs safety after approval, require testing and surveillance programs to monitor the product after commercialization, or impose other conditions, including distribution restrictions or other risk management mechanisms, including REMS, which can materially affect the potential market and profitability of the product. The FDA may prevent or limit further marketing of a product based on the results of post-market studies or surveillance programs. After approval, many types of changes to the approved product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further testing requirements and FDA review and approval.

Drugs manufactured or distributed pursuant to FDA approvals are subject to pervasive and continuing regulation by the FDA, including, among other things, requirements relating to recordkeeping, periodic reporting, product sampling and distribution, advertising and promotion and reporting of adverse experiences with the product. After approval, most changes to the approved product, such as adding new indications or other labeling claims, are subject to prior FDA review and approval. There also are continuing, annual user fee requirements for any marketed products and the establishments at which such products are manufactured, as well as new application fees for supplemental applications with or without clinical data.

In addition, drug manufacturers and other entities involved in the manufacture and distribution of approved drugs are required to register their establishments with the FDA and state agencies, and are subject to periodic unannounced inspections by the FDA and these state agencies for compliance with cGMP requirements. Changes to the manufacturing process are strictly regulated and often require prior FDA approval before being implemented. FDA regulations also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon the sponsor and any third-party manufacturers that the sponsor may decide to use. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain cGMP compliance.

Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical trials to assess new safety risks; or imposition of distribution or other restrictions under a REMS program. Other potential consequences include, among other things:

·restrictions on the marketing or manufacturing of the product, suspension of the approval, or complete withdrawal of the product from the market or product recalls;

·fines, warning letters or holds on post-approval clinical trials;

·refusal of the FDA to approve pending NDAs or supplements to approved NDAs, or suspension or revocation of product license approvals;

·product seizure or detention, or refusal to permit the import or export of products; or

·injunctions or the imposition of civil or criminal penalties.

The FDA strictly regulates marketing, labeling, advertising and promotion of products that are placed on the market. Drugs may be promoted only for the approved indications and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significant liability.

In addition, the distribution of prescription pharmaceutical products is subject to the Prescription Drug Marketing Act, or PDMA, and its implementing regulations, as well as the Drug Supply Chain Security Act, or DSCA, which regulate the distribution and tracing of prescription drugs and prescription drug samples at the federal level, and set minimum standards for the regulation of drug distributors by the states. The PDMA, its implementing regulations and state laws limit the distribution of prescription pharmaceutical product samples and the DSCA imposes requirements to ensure accountability in distribution and to identify and remove counterfeit and other illegitimate products from the market.

NDAs for most new drug products are based on two full clinical studies which must contain substantial evidence of the safety and efficacy of the proposed new product. These applications are submitted under Section 505(b)(1) of the FDCA. The FDA is, however, authorized to approve an alternative type of NDA under Section 505(b)(2) of the FDCA. This type of application allows the applicant to rely, in part, on the FDAs previous findings of safety and efficacy for a similar product, or published literature. Specifically, Section 505(b)(2) applies to NDAs for a drug for which the investigations made to show whether or not the drug is safe for use and effective in use and relied upon by the applicant for approval of the application were not conducted by or for the applicant and for which the applicant has not obtained a right of reference or use from the person by or for whom the investigations were conducted.

Thus, Section 505(b)(2) authorizes the FDA to approve an NDA based on safety and effectiveness data that were not developed by the applicant. NDAs filed under Section 505(b)(2) may provide an alternate and potentially more expeditious pathway to FDA approval for new or improved formulations or new uses of previously approved products. If the Section 505(b)(2) applicant can establish that reliance on the FDAs previous approval is scientifically appropriate, the applicant may eliminate the need to conduct certain preclinical or clinical studies of the new product. The FDA may also require companies to perform additional studies or measurements to support the change from the approved product. The FDA may then approve the new drug candidate for all or some of the label indications for which the referenced product has been approved, as well as for any new indication sought by the Section 505(b)(2) applicant.

Abbreviated New Drug Applications for Generic Drugs

In 1984, with passage of the Hatch-Waxman Amendments to the FDCA, Congress authorized the FDA to approve generic drugs that are the same as drugs previously approved by the FDA under the NDA provisions of the statute. To obtain approval of a generic drug, an applicant must submit an abbreviated new drug application, or ANDA, to the agency. In support of such applications, a generic manufacturer may rely on the preclinical and clinical testing previously conducted for a drug product previously approved under an NDA, known as the reference listed drug, or RLD.

Specifically, in order for an ANDA to be approved, the FDA must find that the generic version is identical to the RLD with respect to the active ingredients, the route of administration, the dosage form, and the strength of the drug. At the same time, the FDA must also determine that the generic drug is bioequivalent to the innovator drug. Under the statute, a generic drug is bioequivalent to a RLD if the rate and extent of absorption of the drug do not show a significant difference from the rate and extent of absorption of the listed drug.

Upon approval of an ANDA, the FDA indicates whether the generic product is therapeutically equivalent to the RLD in its publication Approved Drug Products with Therapeutic Equivalence Evaluations, also referred to as the Orange Book. Physicians and pharmacists consider a therapeutic equivalent generic drug to be fully substitutable for the RLD. In addition, by operation of certain state laws and numerous health insurance programs, the FDAs designation of therapeutic equivalence often results in substitution of the generic drug without the knowledge or consent of either the prescribing physician or patient.

Under the Hatch-Waxman Amendments, the FDA may not approve an ANDA until any applicable period of non-patent exclusivity for the RLD has expired. The FDCA provides a period of five years of non-patent data exclusivity for a new drug containing a new chemical entity. For the purposes of this provision, a new chemical entity, or NCE, is a drug that contains no active moiety that has previously been approved by the FDA in any other NDA. An active moiety is the molecule or ion responsible for the physiological or pharmacological action of the drug substance. In cases where such exclusivity has been granted, an ANDA may not be filed with the FDA until the expiration of five years unless the submission is accompanied by a Paragraph IV certification, in which case the applicant may submit its application four years following the original product approval. The FDCA also provides for a period of three years of exclusivity if the NDA includes reports of one or more new clinical investigations, other than bioavailability or bioequivalence studies, that were conducted by or for the applicant and are essential to the approval of the application. This three-year exclusivity period often protects changes to a previously approved drug product, such as a new dosage form, route of administration, combination or indication.

Upon approval of an NDA or a supplement thereto, NDA sponsors are required to list with the FDA each patent with claims that cover the applicants product or an approved method of using the product. Each of the patents listed by the NDA sponsor is published in the Orange Book. When an ANDA applicant files its application with the FDA, the applicant is required to certify to the FDA concerning any patents listed for the reference product in the Orange Book, except for patents covering methods of use for which the ANDA applicant is not seeking approval. To the extent that the Section 505(b)(2) applicant is relying on studies conducted for an already approved product, the applicant is required to certify to the FDA concerning any patents listed for the approved product in the Orange Book to the same extent that an ANDA applicant would.

Specifically, the applicant must certify with respect to each patent that:

·the required patent information has not been filed;

·the listed patent has expired;

·the listed patent has not expired, but will expire on a particular date and approval is sought after patent expiration; or

·the listed patent is invalid, unenforceable or will not be infringed by the new product.

A certification that the new product will not infringe the already approved products listed patents or that such patents are invalid or unenforceable is called a Paragraph IV certification. If the applicant does not challenge the listed patents or indicates that it is not seeking approval of a patented method of use, the ANDA application will not be approved until all the listed patents claiming the referenced product have expired (other than method of use patents involving indications for which the ANDA applicant is not seeking approval).

If the ANDA applicant has provided a Paragraph IV certification to the FDA, the applicant must also send notice of the Paragraph IV certification to the NDA and patent holders once the ANDA has been accepted for filing by the FDA. The NDA and patent holders may then initiate a patent infringement lawsuit in response to the notice of the Paragraph IV certification. The filing of a patent infringement lawsuit within 45 days after the receipt of a Paragraph IV certification automatically prevents the FDA from approving the ANDA until the earlier of 30 months after the receipt of the Paragraph IV notice, expiration of the patent, or a decision in the infringement case that is favorable to the ANDA applicant.

To the extent that the Section 505(b)(2) applicant is relying on studies conducted for an already approved product, the applicant is required to certify to the FDA concerning any patents listed for the approved product in the Orange Book to the same extent that an ANDA applicant would. As a result, approval of a Section 505(b)(2) NDA can be stalled until all the listed patents claiming the referenced product have expired, until any non-patent exclusivity, such as exclusivity for obtaining approval of a new chemical entity, listed in the Orange Book for the referenced product has expired, and, in the case of a Paragraph IV certification and subsequent patent infringement suit, until the earlier of 30 months, settlement of the lawsuit or a decision in the infringement case that is favorable to the Section 505(b)(2) applicant.

Pediatric Studies and Exclusivity

Under the Pediatric Research Equity Act of 2003, an NDA or supplement thereto must contain data that are adequate to assess the safety and effectiveness of the drug product for the claimed indications in all relevant pediatric subpopulations, and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. With enactment of the FDASIA in 2012, sponsors must also submit pediatric study plans prior to the assessment data. Those plans must contain an outline of the proposed pediatric study or studies the applicant plans to conduct, including study objectives and design, any deferral or waiver requests, and other information required by regulation. The applicant, the FDA, and the FDAs internal review committee must then review the information submitted, consult with each other, and agree upon a final plan. The FDA or the applicant may request an amendment to the plan at any time.

The FDA may, on its own initiative or at the request of the applicant, grant deferrals for submission of some or all pediatric data until after approval of the product for use in adults, or full or partial waivers from the pediatric data requirements. Additional requirements and procedures relating to deferral requests and requests for extension of deferrals are contained in the FDASIA. Unless otherwise required by regulation, the pediatric data requirements do not apply to products with orphan designation.

Pediatric exclusivity is another type of non-patent marketing exclusivity in the United States and, if granted, provides for the attachment of an additional six months of marketing protection to the term of any existing regulatory exclusivity, including the non-patent and orphan exclusivity. This six-month exclusivity may be granted if an NDA sponsor submits pediatric data that fairly respond to a written request from the FDA for such data. The data do not need to show the product to be effective in the pediatric population studied; rather, if the clinical trial is deemed to fairly respond to the FDAs request, the additional protection is granted. If reports of requested pediatric studies are submitted to and accepted by the FDA within the statutory time limits, whatever statutory or regulatory periods of exclusivity or patent protection cover the product are extended by six months. This is not a patent term extension, but it effectively extends the regulatory period during which the FDA cannot approve another application.

Orphan Drug Designation and Exclusivity

Under the Orphan Drug Act, the FDA may designate a drug product as an orphan drug if it is intended to treat a rare disease or condition (generally meaning that it affects fewer than 200,000 individuals in the United States, or more in cases in which there is no reasonable expectation that the cost of developing and making a drug product available in the United States for treatment of the disease or condition will be recovered from sales of the product). A company must request orphan product designation before submitting an NDA. If the request is granted, the FDA will disclose the identity of the therapeutic agent and its potential use. Orphan product designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.

If a product with orphan status receives the first FDA approval for the disease or condition for which it has such designation or for a select indication or use within the rare disease or condition for which it was designated, the product generally will receive orphan product exclusivity. Orphan product exclusivity means that the FDA may not approve any other applications for the same product for the same indication for seven years, except in certain limited circumstances. Competitors may receive approval of different products for the indication for which the orphan product has exclusivity and may obtain approval for the same product but for a different indication. If a drug or drug product designated as an orphan product ultimately receives marketing approval for an indication broader than what was designated in its orphan product application, it may not be entitled to exclusivity.

GAIN Exclusivity for Antibiotics

In 2012, Congress passed legislation known as the Generating Antibiotic Incentives Now Act, or GAIN Act. This legislation is designed to encourage the development of antibacterial and antifungal drug products that treat pathogens that cause serious and life-threatening infections. To that end, the law grants an additional five years of exclusivity upon the approval of an NDA for a drug product designated by FDA as a QIDP. Thus, for a QIDP, the periods of five-year new chemical entity exclusivity, three-year new clinical investigation exclusivity, and seven-year orphan drug exclusivity, would become ten years, eight years, and twelve years, respectively.

A QIDP is defined in the GAIN Act to mean an antibacterial or antifungal drug for human use intended to treat serious or life-threatening infections, including those caused by (1) an antibacterial or antifungal resistant pathogen, including novel or emerging infectious pathogens or (2) certain qualifying pathogens. A qualifying pathogen is a pathogen that has the potential to pose a serious threat to public health (such as resistant Gram-positive pathogens, multi-drug resistant Gram-negative bacteria, multi-drug resistant tuberculosis, and C. difficile) and that is included in a list established and maintained by FDA. A drug sponsor may request the FDA to designate its product as a QIDP any time before the submission of an NDA. The FDA must make a QIDP determination within 60 days of the designation request. A product designated as a QIDP will be granted priority review by the FDA and can qualify for fast track status.

The additional five years of exclusivity under the GAIN Act for drug products designated by the FDA as QIDPs applies only to a drug that is first approved on or after July 9, 2012. Additionally, the five year

exclusivity extension does not apply to: a supplement to an application under FDCA Section 505(b) for any QIDP for which an extension is in effect or has expired; a subsequent application filed with respect to a product approved by the FDA for a change that results in a new indication, route of administration, dosing schedule, dosage form, delivery system, delivery device or strength; or a product that does not meet the definition of a QIDP under Section 505(g) based upon its approved uses. The FDA has designated each of the IV and oral formulations of lefamulin as a QIDP and also granted fast track designations to each of these formulations of lefamulin.

Patent Term Restoration and Extension

A patent claiming a new drug product may be eligible for a limited patent term extension under the Hatch-Waxman Amendments, which permits a patent restoration of up to five years for patent term lost during product development and the FDA regulatory review. The restoration period granted is typically one-half the time between the effective date of an IND and the submission date of an NDA, plus the time between the submission date of an NDA and the ultimate approval date. Patent term restoration cannot be used to extend the remaining term of a patent past a total of 14 years from the products approval date. Only one patent applicable to an approved drug product is eligible for the extension, and the application for the extension must be submitted prior to the expiration of the patent in question. A patent that covers multiple drugs for which approval is sought can only be extended in connection with one of the approvals. The USPTO reviews and approves the application for any patent term extension or restoration in consultation with the FDA.

The 21st Century Cures Act

On December 13, 2016, President Obama signed the 21st Century Cures Act, or Cures Act, into law. The Cures Act is designed to modernize and personalize healthcare, spur innovation and research, and streamline the discovery and development of new therapies through increased federal funding of particular programs. It authorizes increased funding for the FDA to spend on innovation projects. The new law also amends the Public Health Service Act to reauthorize and expand funding for the National Institutes of Health. The Act establishes the NIH Innovation Fund to pay for the cost of development and implementation of a strategic plan, early stage investigators and research. It also charges NIH with leading and coordinating expanded pediatric research. Further, the Cures Act directs the Centers for Disease Control and Prevention to expand surveillance of neurological diseases.

With amendments to the FDCA and the Public Health Service Act, or PHSA, Title III of the Cures Act seeks to accelerate the discovery, development, and delivery of new medicines and medical technologies. To that end, and among other provisions, the Cures Act reauthorizes the existing priority review voucher program for certain drugs intended to treat rare pediatric diseases until 2020; creates a new priority review voucher program for drug applications determined to be material national security threat medical countermeasure applications; revises the FDCA to streamline review of combination product applications; requires FDA to evaluate the potential use of real world evidence to help support approval of new indications for approved drugs; provides a new limited population approval pathway for antibiotic and antifungal drugs intended to treat serious or life-threatening infections; and authorizes FDA to designate a drug as a regenerative advanced therapy, thereby making it eligible for certain expedited review and approval designations.

Regulation Outside the United States

In order to market any product outside of the United States, a company must also comply with numerous and varying regulatory requirements of other countries and jurisdictions regarding quality, safety and efficacy and governing, among other things, clinical trials, marketing authorization, commercial sales and distribution of drug products. Whether or not it obtains FDA approval for a product, the company would need to obtain the necessary approvals by the comparable foreign regulatory authorities before it can commence clinical trials or marketing of the product in those countries or jurisdictions. The approval process ultimately varies between countries and jurisdictions and can involve additional product testing and additional administrative review periods. The time required to obtain approval in other countries and jurisdictions might differ from and be longer than that required to obtain FDA approval. Regulatory approval in one country or jurisdiction does not ensure regulatory approval in another, but a failure or delay in obtaining regulatory approval in one country or jurisdiction may negatively impact the regulatory process in others.

The process governing approval of medicinal products in the European Union follows essentially the same lines as in the United States and, likewise, generally involves satisfactorily completing each of the following:

·preclinical laboratory tests, animal studies and formulation studies all performed in accordance with the applicable E.U. Good Laboratory Practice regulations;

·submission to the relevant national authorities of a clinical trial application, or CTA, which must be approved before human clinical trials may begin;

·performance of adequate and well-controlled clinical trials to establish the safety and efficacy of the product for each proposed indication;

·submission to the relevant competent authorities of a marketing authorization application, or MAA, which includes the data supporting safety and efficacy as well as detailed information on the manufacture and composition of the product in clinical development and proposed labelling;

·satisfactory completion of an inspection by the relevant national authorities of the manufacturing facility or facilities, including those of third parties, at which the product is produced to assess compliance with strictly enforced cGMP;

·potential audits of the non-clinical and clinical trial sites that generated the data in support of the MAA; and

·review and approval by the relevant competent authority of the MAA before any commercial marketing, sale or shipment of the product.

Preclinical Studies

Preclinical tests include laboratory evaluations of product chemistry, formulation and stability, as well as studies to evaluate toxicity in animal studies, in order to assess the potential safety and efficacy of the product. The conduct of the preclinical tests and formulation of the compounds for testing must comply with the relevant E.U. regulations and requirements. The results of the preclinical tests, together with relevant manufacturing information and analytical data, are submitted as part of the CTA.

Clinical Trial Approval

Requirements for the conduct of clinical trials in the European Union including Good Clinical Practice, or GCP, are set forth in the Clinical Trials Directive 2001/20/EC and the GCP Directive 2005/28/EC. Pursuant to Directive 2001/20/EC and Directive 2005/28/EC, as amended, a system for the approval of clinical trials in the European Union has been implemented through national legislation of the E.U. member states. Under this system, approval must be obtained from the competent national authority of each E.U. member state in which a study is planned to be conducted. To this end, a CTA is submitted, which must be supported by an investigational medicinal product dossier, or IMPD, and further supporting information prescribed by Directive 2001/20/EC and Directive 2005/28/EC and other applicable guidance documents. Furthermore, a clinical trial may only be started after a competent ethics committee has issued a favorable opinion on the clinical trial application in that country.

In April 2014, the E.U. passed the new Clinical Trials Regulation, (EU) No 536/2014, which will replace the current Clinical Trials Directive 2001/20/EC. To ensure that the rules for clinical trials are identical throughout the European Union, the new E.U. clinical trials legislation was passed as a regulation that is directly applicable in all E.U. member states. All clinical trials performed in the European Union are required to be conducted in accordance with the Clinical Trials Directive 2001/20/EC until the new Clinical Trials Regulation (EU) No 536/2014 becomes applicable. According to the current plans of EMA, the new Clinical Trials Regulation will become applicable in October 2018. The Clinical Trials Directive 2001/20/EC will, however, still apply three years from the date of entry into application of the Clinical Trials Regulation to (i) clinical trials applications submitted before the entry into application and (ii) clinical trials applications submitted within one year after the entry into application if the sponsor opts for the old system.

·a single set of documents to be prepared and submitted for the application as well as simplified reporting procedures that will spare sponsors from submitting broadly identical information separately to various bodies and different member states;

·a harmonized procedure for the assessment of applications for clinical trials, which is divided in two parts. Part I is assessed jointly by all member states concerned. Part II is assessed separately by each member state concerned;

·strictly defined deadlines for the assessment of clinical trial applications; and

·the involvement of the ethics committees in the assessment procedure in accordance with the national law of the member state concerned but within the overall timelines defined by the Clinical Trials Regulation.

Marketing Authorization

Authorization to market a product in the member states of the European Union proceeds under one of four procedures: a centralized authorization procedure, a mutual recognition procedure, a decentralized procedure or a national procedure.

Centralized Authorization Procedure

The centralized procedure enables applicants to obtain a marketing authorization that is valid in all E.U. member states based on a single application. Certain medicinal products, including products developed by means of biotechnological processes must undergo the centralized authorization procedure for marketing authorization, which, if granted by the European Commission, is automatically valid in all 28 E.U. member states. The EMA and the European Commission administer this centralized authorization procedure pursuant to Regulation (EC) No 726/2004.

Pursuant to Regulation (EC) No 726/2004, this procedure is mandatory for:

·medicinal products developed by means of one of the following biotechnological processes:

·recombinant DNA technology;

·controlled expression of genes coding for biologically active proteins in prokaryotes and eukaryotes including transformed mammalian cells; and

·medicinal products for human use containing a new active substance that, on the date of effectiveness of this regulation, was not authorized in the European Union, and for which the therapeutic indication is the treatment of any of the following diseases:

·medicinal products that are designated as orphan medicinal products pursuant to Regulation (EC) No 141/2000.

The centralized authorization procedure is optional for other medicinal products if they contain a new active substance or if the applicant shows that the medicinal product concerned constitutes a significant therapeutic, scientific or technical innovation or that the granting of authorization is in the interest of patients in the European Union.

Administrative Procedure

Under the centralized authorization procedure, the EMAs Committee for Medicinal Products for Human Use, or CHMP serves as the scientific committee that renders opinions about the safety, efficacy and quality of medicinal products for human use on behalf of the EMA. The CHMP is composed of experts nominated by each member states national authority for medicinal products, with one of them appointed to act as Rapporteur for the co-ordination of the evaluation with the possible assistance of a further member of the Committee acting as a Co-Rapporteur. After approval, the Rapporteur(s) continue to monitor the product throughout its life cycle. The CHMP has 210 days, to adopt an opinion as to whether a marketing authorization should be granted. The process usually takes longer in case additional information is requested, which triggers clock-stops in the procedural timelines. The process is complex and involves extensive consultation with the regulatory authorities of member states and a number of experts. When an application is submitted for a marketing authorization in respect of a drug that is of major interest from the point of view of public health and in particular from the viewpoint of therapeutic innovation, the applicant may pursuant to Article 14(9) Regulation (EC) No 726/2004 request an accelerated assessment procedure. If the CHMP accepts such request, the time-limit of 210 days will be reduced to 150 days but it is possible that the CHMP can revert to the standard time-limit for the centralized procedure if it considers that it is no longer appropriate to conduct an accelerated assessment. Once the procedure is completed, a European Public Assessment Report, or EPAR, is produced. If the opinion is negative, information is given as to the grounds on which this conclusion was reached. After the adoption of the CHMP opinion, a decision on the MAA must be adopted by the European Commission, after consulting the E.U. member states, which in total can take more than 60 days.

Conditional Approval

In specific circumstances, E.U. legislation (Regulation (EC) No 726/2004 and Regulation (EC) No 507/2006 on Conditional Marketing Authorisations for Medicinal Products for Human Use) enables applicants to obtain a conditional marketing authorization prior to obtaining the comprehensive clinical data required for an application for a full marketing authorization. Such conditional approvals may be granted for product candidates (including medicines designated as orphan medicinal products), if (1) the risk-benefit balance of the product candidate is positive, (2) it is likely that the applicant will be in a position to provide the required comprehensive clinical trial data, (3) the product fulfills unmet medical needs and (4) the benefit to public health of the immediate availability on the market of the medicinal product concerned outweighs the risk inherent in the fact that additional data are still required. A conditional marketing authorization may contain specific obligations to be fulfilled by the marketing authorization holder, including obligations with respect to the completion of ongoing or new studies, and with respect to the collection of pharmacovigilance data. Conditional marketing authorizations are valid for one year, and may be renewed annually, if the risk-benefit balance remains positive, and after an assessment of the need for additional or modified conditions and/or specific obligations. The timelines for the centralized procedure described above also apply with respect to the review by the CHMP of applications for a conditional marketing authorization.

Under Regulation (EC) No 726/2004, products for which the applicant can demonstrate that comprehensive data (in line with the requirements laid down in Annex I of Directive 2001/83/EC, as amended) cannot be provided (due to specific reasons foreseen in the legislation) might be eligible for marketing authorization under exceptional circumstances. This type of authorization is reviewed annually to reassess the risk-benefit balance. The fulfillment of any specific procedures/obligations imposed as part of the marketing authorization under exceptional circumstances is aimed at the provision of information on the safe and effective use of the product and will normally not lead to the completion of a full dossier/approval.

Market Authorizations Granted by Authorities of E.U. Member States

In general, if the centralized procedure is not followed, there are three alternative procedures to obtain a marketing authorization in (one or several) E.U. member states as prescribed in Directive 2001/83/EC:

·The decentralized procedure allows applicants to file identical applications to several E.U. member states and receive simultaneous national approvals based on the recognition by E.U. member states of an assessment by a reference member state.

·The national procedure is only available for products intended to be authorized in a single E.U. member state.

·A mutual recognition procedure similar to the decentralized procedure is available when a marketing authorization has already been obtained in at least one E.U. member state.

A marketing authorization may be granted only to an applicant established in the European Union.

Pediatric Studies

Prior to obtaining a marketing authorization in the European Union, applicants have to demonstrate compliance with all measures included in an EMA-approved Pediatric Investigation Plan, or PIP, covering all subsets of the pediatric population, unless the EMA has granted a product-specific waiver, a class waiver, or a deferral for one or more of the measures included in the PIP. The respective requirements for all marketing authorization procedures are set forth in Regulation (EC) No 1901/2006, which is referred to as the Pediatric Regulation. This requirement also applies when a company wants to add a new indication, pharmaceutical form or route of administration for a medicine that is already authorized. The Pediatric Committee of the EMA, or PDCO, may grant deferrals for some medicines, allowing a company to delay development of the medicine in children until there is enough information to demonstrate its effectiveness and safety in adults. The PDCO may also grant waivers when development of a medicine in children is not needed or is not appropriate, such as for diseases that only affect the elderly population.

Before a marketing authorization application can be filed, or an existing marketing authorization can be amended, the EMA determines that companies actually comply with the agreed studies and measures listed in each relevant PIP.

Period of Authorization and Renewals

A marketing authorization, other than a conditional marketing authorization, is initially valid for five years and the marketing authorization may be renewed after five years on the basis of a re-evaluation of the risk-benefit balance by the EMA or by the competent authority of the authorizing member state. To this end, the marketing authorization holder must provide the EMA or the competent authority with a consolidated version of the file in respect of quality, safety and efficacy, including all variations introduced since the marketing authorization was granted, at least six months before the marketing authorization ceases to be valid. Once renewed, the marketing authorization is valid for an unlimited period, unless the European Commission or the competent authority decides, on justified grounds relating to pharmacovigilance, to proceed with one additional five-year renewal. Any authorization which is not followed by the actual placing of the drug on the E.U. market (in case of centralized procedure) or on the market of the authorizing member state within three years after authorization ceases to be valid (the so-called sunset clause).

European Union legislation also provides for a system of regulatory data and market exclusivity. According to Article 14(11) of Regulation (EC) No 726/2004, as amended, and Article 10(1) of Directive 2001/83/EC, as amended, upon receiving marketing authorization, new chemical entities approved on the basis of complete independent data package benefit from eight years of data exclusivity and an additional two years of market exclusivity. Data exclusivity prevents regulatory authorities in the European Union from referencing the innovators data to assess a generic (abbreviated) application. During the additional two-year period of market exclusivity, a generic marketing authorization application can be submitted, and the innovators data may be referenced, but no generic medicinal product can be marketed until the expiration of the market exclusivity. The overall ten-year period will be extended to a maximum of eleven years if, during the first eight years of those ten years, the marketing authorization holder, or MAH, obtains an authorization for one or more new therapeutic indications which, during the scientific evaluation prior to their authorization, are held to bring a significant clinical benefit in comparison with existing therapies. Even if a compound is considered to be a new chemical entity and the innovator is able to gain the period of data exclusivity, another company nevertheless could also market another version of the drug if such company obtained marketing authorization based on an MAA with a complete independent data package of pharmaceutical test, preclinical tests and clinical trials.

Transparency

There is an increasing trend in the E.U. towards greater transparency and, while the manufacturing or quality information in marketing authorization dossiers is currently generally protected as confidential information, the EMA and national regulatory authorities are now liable to disclose much of the non-clinical and clinical information, including the full clinical study reports, in response to freedom of information requests after the marketing authorization has been granted. In October 2014, the EMA adopted a policy under which clinical study reports would be posted on the agencys website following the grant, denial or withdrawal of a marketing authorization application, subject to procedures for limited redactions and protection against unfair commercial use. Additional transparency provisions are contained in the new Clinical Trials Regulation (EU) No 536/2014 that will take effect in May 2016 at the earliest.

Regulatory Requirements After a Marketing Authorization has been Obtained

If we obtain authorization for a medicinal product in the European Union, we will be required to comply with a range of requirements applicable to the manufacturing, marketing, promotion and sale of medicinal products:

Pharmacovigilance and Other Requirements

We will, for example, have to comply with the E.U.s stringent pharmacovigilance or safety reporting rules, pursuant to which post-authorization studies and additional monitoring obligations can be imposed. E.U. regulators may conduct inspections to verify our compliance with applicable requirements, and we will have to continue to expend time, money and effort to remain compliant. Non-compliance with E.U. requirements regarding safety monitoring or pharmacovigilance, and with requirements related to the development of products for the pediatric population, can also result in significant financial penalties in the European Union. Similarly, failure to comply with the European Unions requirements regarding the protection of individual personal data can also lead to significant penalties and sanctions. Individual E.U. member states may also impose various sanctions and penalties in case we do not comply with locally applicable requirements.

Manufacturing

The manufacturing of authorized drugs, for which a separate manufacturers license is mandatory, must be conducted in strict compliance with the EMAs GMP requirements and comparable requirements of other regulatory bodies in the European Union, which mandate the methods, facilities and controls used in manufacturing, processing and packing of drugs to assure their safety and identity. The EMA enforces its GMP requirements through mandatory registration of facilities and inspections of those facilities. The EMA may have a coordinating role for these inspections while the responsibility for carrying them out rests with the member states competent authority under whose responsibility the manufacturer falls. Failure to comply with these requirements could interrupt supply and result in delays, unanticipated costs and lost revenues, and could subject

the applicant to potential legal or regulatory action, including but not limited to warning letters, suspension of manufacturing, seizure of product, injunctive action or possible civil and criminal penalties.

Marketing and Promotion

The marketing and promotion of authorized drugs, including industry-sponsored continuing medical education and advertising directed toward the prescribers of drugs and/or the general public, are strictly regulated in the European Union under Directive 2001/83EC, as amended. The applicable regulations aim to ensure that information provided by holders of marketing authorizations regarding their products is truthful, balanced and accurately reflects the safety and efficacy claims authorized by the EMA or by the competent authority of the authorizing member state. Failure to comply with these requirements can result in adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties.

Patent Term Extension

To compensate the patentee for delays in obtaining a marketing authorization for a patented product, a supplementary certificate, or SPC, may be granted extending the exclusivity period for that specific product by up to five years. Applications for SPCs must be made to the relevant patent office in each E.U. member state and the granted certificates are valid only in the member state of grant. An application has to be made by the patent owner within six months of the first marketing authorization being granted in the European Union (assuming the patent in question has not expired, lapsed or been revoked) or within six months of the grant of the patent (if the marketing authorization is granted first). In the context of SPCs, the term product means the active ingredient or combination of active ingredients for a medicinal product and the term patent means a patent protecting such a product or a new manufacturing process or application for it. The duration of an SPC is calculated as the difference between the patents filing date and the date of the first marketing authorization, minus five years, subject to a maximum term of five years.

A six-month pediatric extension of an SPC may be obtained where the patentee has carried out an agreed pediatric investigation plan, the authorized product information includes information on the results of the studies and the product is authorized in all member states of the European Union.

Brexit and the Regulatory Framework in the United Kingdom

On June 23, 2016, the electorate in the United Kingdom voted in favor of leaving the European Union (commonly referred to as Brexit). The withdrawal of the U.K. from the European Union will take effect either on the effective date of the withdrawal agreement or, in the absence of agreement, two years after the U.K. provides a notice of withdrawal pursuant to the E.U. Treaty. The U.K. Prime Minister has stated that notice of withdrawal will be given by the end of March 2017. As the regulatory framework for pharmaceutical products in the U.K. covering quality, safety and efficacy of pharmaceutical products, clinical trials, marketing authorization, commercial sales and distribution of pharmaceutical products is derived from European Union directives and regulations, Brexit could materially impact the future regulatory regime which applies to products and the approval of product candidates in the U.K. It remains to be seen how, if at all, Brexit will impact regulatory requirements for product candidates and products in the U.K and the European Union.

Pharmaceutical Coverage, Pricing and Reimbursement

In the United States and markets in other countries, patients who are prescribed treatments for their conditions and providers performing the prescribed services generally rely on third-party payors to reimburse all or part of the associated healthcare costs. Significant uncertainty exists as to the coverage and reimbursement status of products approved by the FDA and other government authorities. Thus, even if a product candidate is approved, sales of the product will depend, in part, on the extent to which third-party payors, including government health programs in the United States such as Medicare and Medicaid, commercial health insurers and managed care organizations, provide coverage, and establish adequate reimbursement levels for, the product. The process for determining whether a payor will provide coverage for a product may be separate from the process for setting the price or reimbursement rate that the payor will pay for the product once coverage is approved. Third-party payors are increasingly challenging the prices charged, examining the medical necessity, and reviewing the cost-effectiveness of medical products and services and imposing controls to manage costs. Third-party payors may limit coverage to specific products on an approved list, also known as a formulary, which might not include all of the approved products for a particular indication.

To secure coverage and reimbursement for any product that might be approved for sale, a company may need to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of the product, in addition to the costs required to obtain FDA or other comparable marketing approvals. Nonetheless, product candidates may not be considered medically necessary or cost effective. A decision by a third-party payor not to cover a product candidate could reduce physician utilization once the product is approved and have a material adverse effect on sales, results of operations and financial condition. Additionally, a payors decision to provide coverage for a product does not imply that an adequate reimbursement rate will be approved. Further, one payors determination to provide coverage for a drug product does not assure that other payors will also provide coverage and reimbursement for the product, and the level of coverage and reimbursement can differ significantly from payor to payor.

The containment of healthcare costs also has become a priority of federal, state and foreign governments and the prices of drugs have been a focus in this effort. Governments have shown significant interest in implementing cost-containment programs, including price controls, restrictions on reimbursement and requirements for substitution of generic products. Adoption of price controls and cost-containment measures, and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit a companys revenue generated from the sale of any approved products. Coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which a company or its collaborators receive marketing approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

Outside the United States, ensuring adequate coverage and payment for a product also involves challenges. Pricing of prescription pharmaceuticals is subject to governmental control in many countries. Pricing negotiations with governmental authorities can extend well beyond the receipt of regulatory marketing approval for a product and may require a clinical trial that compares the cost effectiveness of a product to other available therapies. The conduct of such a clinical trial could be expensive and result in delays in commercialization.

In the European Union, pricing and reimbursement schemes vary widely from country to country. Some countries provide that products may be marketed only after a reimbursement price has been agreed. Some countries may require the completion of additional studies that compare the cost-effectiveness of a particular drug candidate to currently available therapies or so called health technology assessments, in order to obtain reimbursement or pricing approval. For example, the European Union provides options for its member states to restrict the range of products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. E.U. European Union member states may approve a specific price for a product or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the product on the market. Other member states allow companies to fix their own prices for products, but monitor and control prescription volumes and issue guidance to physicians to limit prescriptions. Recently, many countries in the European Union have increased the amount of discounts required on pharmaceuticals and these efforts could continue as countries attempt to manage healthcare expenditures, especially in light of the severe fiscal and debt crises experienced by many countries in the European Union. The downward pressure on health care costs in general, particularly prescription drugs, has become intense. As a result, increasingly high barriers are being erected to the entry of new products. Political, economic and regulatory developments may further complicate pricing negotiations, and pricing negotiations may continue after reimbursement has been obtained. Reference pricing used by various European Union member states, and parallel trade, i.e., arbitrage between low-priced and high-priced member states, can further reduce prices. There can be no assurance that any country that has price controls or reimbursement limitations for pharmaceutical products will allow favorable reimbursement and pricing arrangements for any products, if approved in those countries.

Healthcare Law and Regulation

Healthcare providers and third party payors play a primary role in the recommendation and prescription of drug products that are granted marketing approval. Arrangements with providers, consultants, third party payors and customers are subject to broadly applicable fraud and abuse, anti-kickback, false claims laws, reporting of payments to physicians and teaching physicians and patient privacy laws and regulations and other healthcare laws and regulations that may constrain business and/or financial arrangements. Restrictions under applicable federal and state healthcare laws and regulations, include the following:

or indirectly, in cash or in kind, to induce or reward either the referral of an individual for, or the purchase, order or recommendation of, any good or service, for which payment may be made, in whole or in part, under a federal healthcare program such as Medicare and Medicaid;

·the federal civil and criminal false claims laws, including the civil False Claims Act and civil monetary penalty laws, which prohibit individuals or entities from, among other things, knowingly presenting, or causing to be presented, to the federal government, claims for payment that are false, fictitious or fraudulent or knowingly making, using or causing to be made or used a false record or statement to avoid, decrease or conceal an obligation to pay money to the federal government;

·the federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which created additional federal criminal laws that prohibit, among other things, knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program or making false statements relating to healthcare matters;

·HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act and their regulations, including the Final Omnibus Rule published in January 2013, which impose obligations, including mandatory contractual terms, with respect to safeguarding the privacy, security and transmission of individually identifiable health information;

·the federal false statements statute, which prohibits knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false statement in connection with the delivery of or payment for healthcare benefits, items or services;

·the federal transparency requirements known as the federal Physician Payments Sunshine Act, under the Patient Protection and Affordable Care Act, as amended by the Health Care Education Reconciliation Act, or the Affordable Care Act, which requires certain manufacturers of drugs, devices, biologics and medical supplies to report annually to the Centers for Medicare & Medicaid Services, or CMS, within the United States Department of Health and Human Services, information related to payments and other transfers of value made by that entity to physicians and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members; and

·analogous state and foreign laws and regulations, such as state anti-kickback and false claims laws, which may apply to healthcare items or services that are reimbursed by non-governmental third-party payors, including private insurers.

Some state laws require pharmaceutical companies to comply with the pharmaceutical industrys voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government in addition to requiring drug manufacturers to report information related to payments to physicians and other health care providers or marketing expenditures. State and foreign laws also govern the privacy and security of health information in some circumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

Healthcare Reform

A primary trend in the United States healthcare industry and elsewhere is cost containment. There have been a number of federal and state proposals during the last few years regarding the pricing of pharmaceutical and biopharmaceutical products, limiting coverage and reimbursement for drugs and other medical products, government control and other changes to the healthcare system in the United States.

In March 2010, the United States Congress enacted the Affordable Care Act, or the ACA, which, among other things, includes changes to the coverage and payment for products under government health care programs. Among the provisions of the Affordable Care Act of importance to potential drug candidates are:

·an annual, nondeductible fee on any entity that manufactures or imports specified branded prescription drugs and biologic agents, apportioned among these entities according to their market share in certain government healthcare programs, although this fee would not apply to sales of certain products approved exclusively for orphan indications;

·expansion of eligibility criteria for Medicaid programs by, among other things, allowing states to offer Medicaid coverage to certain individuals with income at or below 133% of the federal poverty level, thereby potentially increasing a manufacturers Medicaid rebate liability;

·expanded manufacturers rebate liability under the Medicaid Drug Rebate Program by increasing the minimum rebate for both branded and generic drugs and revising the definition of average manufacturer price, or AMP, for calculating and reporting Medicaid drug rebates on outpatient prescription drug prices and extending rebate liability to prescriptions for individuals enrolled in Medicare Advantage plans;

·addressed a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs that are inhaled, infused, instilled, implanted or injected;

·expanded the types of entities eligible for the 340B drug discount program;

·established the Medicare Part D coverage gap discount program by requiring manufacturers to provide a 50% point-of-sale-discount off the negotiated price of applicable brand drugs to eligible beneficiaries during their coverage gap period as a condition for the manufacturers outpatient drugs to be covered under Medicare Part D;

·a new Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct comparative clinical effectiveness research, along with funding for such research;

·the Independent Payment Advisory Board, or IPAB, which has authority to recommend certain changes to the Medicare program to reduce expenditures by the program that could result in reduced payments for prescription drugs. However, the IPAB implementation has been not been clearly defined. PPACA provided that under certain circumstances, IPAB recommendations will become law unless Congress enacts legislation that will achieve the same or greater Medicare cost savings; and

·established the Center for Medicare and Medicaid Innovation within CMS to test innovative payment and service delivery models to lower Medicare and Medicaid spending, potentially including prescription drug spending. Funding has been allocated to support the mission of the Center for Medicare and Medicaid Innovation from 2011 to 2019.

Other legislative changes have been proposed and adopted in the United States since the ACA was enacted. For example, in August 2011, the Budget Control Act of 2011, among other things, created measures for spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 trillion for the years 2012 through 2021, was unable to reach required goals, thereby triggering the legislations automatic reduction to several government programs. This includes aggregate reductions of Medicare payments to providers of up to 2% per fiscal year, which went into effect in April 2013 and will remain in effect through 2024 unless additional Congressional action is taken. In January 2013, President Obama signed into law the American Taxpayer Relief Act of 2012, which, among other things, further reduced Medicare payments to several providers, including hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years.

With the new Administration and Congress, there will likely be additional legislative changes, including repeal and replacement of certain provisions of the ACA. In January 2017, Congress voted to adopt a budget resolution for fiscal year 2017, or the Budget Resolution, that authorizes the implementation of legislation that would repeal portions of the ACA. The Budget Resolution is not a law, however, it is widely viewed as the first step toward the passage of legislation that would repeal certain aspects of the ACA. Further, on January 20, 2017, President Trump signed an Executive Order directing federal agencies with authorities and responsibilities under the ACA to waive, defer, grant exemptions from, or delay the implementation of any provision of the ACA that would impose a fiscal or regulatory burden on states, individuals, healthcare providers, health insurers, or manufacturers of pharmaceuticals or medical devices. In March 2017, the United States House of Representatives introduced a Budget Resolution to replace the ACA will a tax credit based system. It is uncertain if these changes will be approved by the United States Senate or the President.

The President and congressional leaders have expressed interest in repealing certain ACA provisions and

replacing them with alternatives that may be less costly and provide state Medicaid programs and private health plans more flexibility. It is possible that these repeal and replacement initiatives, if enacted into law, could ultimately result in fewer individuals having health insurance coverage or in individuals having insurance coverage with less generous benefits. The scope of potential future legislation to repeal and replace ACA provisions is highly uncertain in many respects, and it is possible that some of the ACA provisions that generally are not favorable for the research-based pharmaceutical industry could also be repealed along with ACA coverage expansion provisions. However, at this time the coverage expansion provisions of the ACA appear most likely to be repealed and replaced.

Employees

As of March 15, 2017, we had 59 employees, 38 of our employees are located in Vienna, Austria and 21 of our employees were located in King of Prussia, Pennsylvania. Our employees in Austria are subject to the collective bargaining agreement of the chemical industry. This is an annual agreement between the employer representatives and the trade union of an industry. It defines conditions of employment, such as minimum wages, working hours and conditions, overtime payments, vacations and other matters. We do not have a works council, which would require employee representatives on our supervisory board.

We consider our relations with our employees to be good.

Our Corporate Information

We were incorporated in October 2005 in Austria under the name Nabriva Therapeutics Forschungs GmbH, a limited liability company organized under Austrian law, as a spin-off from Sandoz GmbH and commenced operations in February 2006. In 2007, we transformed into a stock corporation (Aktiengesellschaft) under the name Nabriva Therapeutics AG. We are incorporated under the laws of the Republic of Austria and registered at the Commercial Register of the Commercial Court of Vienna. Our executive offices are located at Leberstrasse 20, 1110 Vienna, Austria, and our telephone number is +43 (0)1 740 930. Our U.S. operations are conducted by our wholly-owned subsidiary Nabriva Therapeutics US, Inc., a Delaware corporation established in August 2014 and located at 1000 Continental Drive, Suite 600, King of Prussia, PA 19406. Our website address is www.nabriva.com. The information contained on, or that can be accessed from, our website does not form part of this Annual Report. Our agent for service of process in the United States is CT Corporation System, 111 Eighth Avenue, New York, New York 10011.

On March 24, 2017, our supervisory board authorized management to pursue a plan for the redomiciliation of our ultimate parent company from Austria to Ireland. We are working with our advisors to structure and implement such a redomiciliation plan. We currently anticipate that the plan, which will require further approval of the supervisory board, will be presented to our shareholders for their consideration during 2017. We may abandon our redomiciliation plan at any time and there can be no assurance that we will redomicile from Austria to Ireland during 2017, or at all.

Available Information

We make available free of charge through our website our annual report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K and amendments to those reports filed or furnished pursuant to Sections 13(a) and 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act. Previously, as a foreign private issuer, we filed our Annual Report on Form 20-F and furnished information on Form 6-K. We make these reports available through our website as soon as reasonably practicable after we electronically file such reports with, or furnish such reports to, the SEC. You can find, copy and inspect information we file at the SECs public reference room, which is located at 100 F Street, N.E., Room 1580, Washington, DC 20549. Please call the SEC at 1-800-SEC-0330 for more information about the operation of the SECs public reference room. You can review our electronically filed reports and other information that we file with the SEC on the SECs web site at http://www.sec.gov. We also make available, free of charge on our website, the reports filed with the SEC by our supervisory board members, management board member, senior managers and 10% shareholders pursuant to Section 16 under the Exchange Act as soon as reasonably practicable after copies of those filings are provided to us by those persons. The information contained on, or that can be access through, our website is not a part of or incorporated by reference in this Annual Report on Form 10-K.

You should consider carefully the risks and uncertainties described below, together with all of the other information in this Form 10-K. If any of the following risks are realized, our business, financial condition, results of operations and prospects could be materially and adversely affected. The risks described below are not the only risks facing us. Risks and uncertainties not currently known to us or that we currently deem to be immaterial also may materially adversely affect our business, financial condition, results of operations and/or prospects.

Risks Related to Our Financial Position and Need for Additional Capital

We have incurred significant losses since our inception. We expect to incur losses for at least the next several years and may never generate profits from operations or maintain profitability.

Since inception, we have incurred significant operating losses. Our net losses were $54.9 million for the year ended December 31, 2016, $47.0 million for the year ended December 31, 2015 and $14.2 million for the year ended December 31, 2014. As of December 31, 2016, we had accumulated losses of $204.8 million. To date, we have financed our operations primarily through the sale of our equity securities, including our American Depositary Shares, or ADSs, and private placements of our common shares, convertible loans and research and development support from governmental grants and loans. We have devoted substantially all of our efforts to research and development, including clinical trials. We have not completed development of any drugs. We expect to continue to incur significant expenses and increasing operating losses for at least the next several years. The net losses we incur may fluctuate significantly from quarter-to-quarter and year-to-year.

We anticipate that our expenses will increase substantially as we progress our two international Phase 3 clinical trials of our lead product candidate, lefamulin, for the treatment of community-acquired bacterial pneumonia, or CABP. We initiated the first of these clinical trials, which we refer to as LEAP 1, in September 2015 and initiated the second trial, which we refer to as LEAP 2, in April 2016. If the results of these two trials are favorable, including achievement of the primary efficacy endpoints of the trials, we expect to submit applications for marketing approval for lefamulin for the treatment of CABP in both the United States and Europe in 2018. We also continue to characterize the clinical pharmacology of lefamulin. If we obtain marketing approval of lefamulin for CABP or another indication, we also expect to incur significant sales, marketing, distribution and manufacturing expenses.

In addition, our expenses will increase if and as we:

·initiate or continue the research and development of lefamulin for additional indications and of our other product candidates;

·ultimately establish a sales, marketing and distribution infrastructure and scale up manufacturing capabilities to commercialize any product candidates for which we receive marketing approval;

·in-license or acquire other products, product candidates or technologies;

·maintain, expand and protect our intellectual property portfolio;

·expand our physical presence in the United States; and

·add operational, financial and management information systems and personnel, including personnel to support our product development, our operations as a public company and our planned future commercialization efforts.

Our ability to generate profits from operations and remain profitable depends on our ability to successfully develop and commercialize drugs that generate significant revenue. Based on our current plans, we do not expect to generate significant revenue unless and until we obtain marketing approval for, and commercialize,

·contracting for the manufacture of and obtaining commercial quantities of lefamulin; and

·negotiating and securing adequate reimbursement from third-party payors for lefamulin.

We may never succeed in these activities and, even if we do, may never generate revenues that are significant enough to generate profits from operations. Even if we do generate profits from operations, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to generate profits from operations and remain profitable would decrease the value of our company and could impair our ability to raise capital, expand our business, maintain our research and development efforts, diversify our product offerings or continue our operations. A decline in the value of our company could also cause our shareholders to lose all or part of their investment.

We will need substantial additional funding. If we are unable to raise capital when needed or on acceptable terms, we could be forced to delay, reduce or eliminate our product development programs or future commercialization efforts.

We expect our research and development, commercialization and other expenses to increase substantially in connection with our ongoing activities, particularly as we continue development of and potentially seek marketing approval for lefamulin and, possibly, other product candidates and continue our research activities. Our expenses will increase if we suffer any delays in our Phase 3 clinical program for lefamulin for CABP, including delays in enrollment of patients. If we obtain marketing approval for lefamulin or any other product candidate that we develop, we expect to incur significant commercialization expenses related to product sales, marketing, distribution and manufacturing.

Furthermore, we expect to continue to incur additional costs associated with operating as a public company.

Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we could be forced to delay, reduce or eliminate our research and development programs or any future commercialization efforts.

We expect that our existing cash, cash equivalents and short-term investments, will be sufficient to enable us to fund our operating expenses and capital expenditure requirements at least into the second quarter of 2018 and to obtain top-line data for both our Phase 3 clinical trials of lefamulin. We have based these estimates on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect. These estimates assume, among other things, that we do not obtain any additional funding through grants and clinical trial support, collaboration agreements or debt financings.

Our future capital requirements will depend on many factors, including:

·the costs and timing of process development and manufacturing scale-up activities associated with lefamulin;

·the costs, timing and outcome of regulatory review of lefamulin;

·the costs of commercialization activities for lefamulin if we receive, or expect to receive, marketing approval, including the costs and timing of establishing product sales, marketing, distribution and outsourced manufacturing capabilities;

·subject to receipt of marketing approval, revenue received from commercial sales of lefamulin;

·the costs of developing lefamulin for the treatment of additional indications;

·our ability to establish collaborations on favorable terms, if at all;

·the scope, progress, results and costs of product development of BC-7013 and any other product candidates that we may develop;

·the extent to which we in-license or acquire rights to other products, product candidates or technologies;

·the rate of the expansion of our physical presence in the United States; and

·the costs of operating as a public company in the United States.

Conducting clinical trials is a time consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain marketing approval and achieve product sales. Our commercial revenues, if any, will be derived from sales of lefamulin or any other products that we successfully develop, none of which we expect to be commercially available for several years, if at all. In addition, if approved, lefamulin or any other product candidate that we develop, in-license or acquire may not achieve commercial success. Accordingly, we will need to obtain substantial additional financing to achieve our business objectives.

Adequate additional financing may not be available to us on acceptable terms, or at all. In addition, we may seek additional capital due to favorable market conditions or strategic considerations, even if we believe that we have sufficient funds for our current or future operating plans.

Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaborations, and funding from local and international government entities and non-government organizations in the disease areas addressed by our product candidates and marketing, distribution or licensing arrangements. To the extent that we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect your rights as a security holder. Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. In addition, debt service obligations under any debt financings may limit the availability of our cash for other purposes, and we may be unable to make interest payments or repay the principal of such debt financings when due.

If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or to grant licenses on terms that may not be favorable to us.

If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Our limited operating history may make it difficult for you to evaluate the success of our business to date and to assess our future viability.

Our operations to date have been limited to organizing and staffing our company, developing and securing our technology, raising capital and undertaking preclinical studies and clinical trials of our product candidates. We have not yet demonstrated our ability to successfully complete development of any product candidates, obtain marketing approvals, manufacture a commercial scale product, or arrange for a third party to do so on our behalf, or conduct sales and marketing activities necessary for successful product commercialization. Consequently, any predictions you make about our future success or viability may not be as accurate as they could be if we had a longer operating history.

In addition, as a new business, we may encounter unforeseen expenses, difficulties, complications, delays and other known and unknown factors. We will need to transition from a company with a research and development focus to a company capable of supporting commercial activities. We may not be successful in such a transition.

We have relied on, and expect to continue to rely on, certain government grants and funding from the Austrian government. Should these funds cease to be available, or our eligibility be reduced, or if we are required to repay any of these funds, this could impact our ongoing need for funding and the timeframes within which we currently expect additional funding will be required.

As a company that carries out extensive research and development activities, we benefit from the Austrian research and development support regime, under which we are eligible to receive a research premium from the Austrian government equal to 12% (10%, in the case of fiscal years prior to 2016) of a specified research and development cost base. Qualifying expenditures largely comprise research and development activities conducted in Austria, however, the research premium is also available for certain related third-party expenses with additional limitations. We received research premiums of $4.3 million for the year ended December 31, 2015 and $1.4 million for the year ended December 31, 2014. We also expect to receive a research premium for our qualified 2016 expenditures. However, as we increase our personnel and expand our business outside of Austria, we may not be able to continue to claim research premiums to the same extent as we have in previous years, as some research and development activities may no longer be considered to occur in Austria. As research premiums that have been paid out already may be audited by the tax authorities, there is a risk that parts of the submitted cost base may not be considered as eligible and therefore repayments may have to be made.

Risks Related to Product Development and Commercialization

We depend heavily on the success of our lead product candidate, lefamulin, which we are developing for CABP and other indications. If we are unable to complete our Phase 3 clinical program for lefamulin for CABP as and when expected and obtain marketing approvals for lefamulin, or if thereafter we fail to commercialize lefamulin or experience significant delays in doing so, our business will be materially harmed.

We have invested a significant portion of our efforts and financial resources in the development of lefamulin. There remains a significant risk that we will fail to successfully develop lefamulin for CABP or any other indication. Based on our estimates regarding patient enrollment, we expect to have top-line data from LEAP 1 in the third quarter of 2017. With respect to LEAP 2, based on current projections, we expect to complete patient enrollment in the fourth quarter of 2017, and we anticipate receiving top-line data for LEAP 2 in the first quarter of 2018. Our ability to meet our target timing will depend on our enrollment rates. A significant delay in enrollment would result in delays to our development timeline and additional development costs beyond what we have budgeted. If we ultimately obtain favorable results from our Phase 3 clinical program for lefamulin for CABP, we do not expect to submit applications for marketing approval for lefamulin for this indication until 2018.

Our ability to generate product revenues, which may not occur for several years, if ever, will depend heavily on our obtaining marketing approval for and commercializing lefamulin. The success of lefamulin will depend on a number of factors, including the following:

·receipt of marketing approvals from applicable regulatory authorities for lefamulin for the treatment of CABP;

·launching commercial sales of lefamulin, if and when approved, whether alone or in collaboration with third parties;

·acceptance of lefamulin, if and when approved, by patients, the medical community and third- party payors;

·effectively competing with other therapies;

·maintaining a continued acceptable safety profile of lefamulin following approval;

·obtaining and maintaining patent and trade secret protection and regulatory exclusivity; and

·protecting our rights in our intellectual property portfolio.

Successful development of lefamulin for the treatment of additional indications, if any, or for use in other patient populations and our ability, if it is approved, to broaden the label for lefamulin will depend on similar factors.

If we do not achieve one or more of these factors in a timely manner or at all, we could experience significant delays or an inability to successfully commercialize lefamulin for CABP or for any additional indications, which would materially harm our business.

If clinical trials of lefamulin or any of our other product candidates fail to demonstrate safety and efficacy to the satisfaction of the U.S. Food and Drug Administration, or FDA, regulatory authorities in the European Union, or other regulatory authorities or do not otherwise produce favorable results, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of lefamulin or any other product candidate.

Before obtaining marketing approval from regulatory authorities for the sale of any product candidate, we must complete preclinical development and early clinical trials, including Phase 1 clinical trials, in addition to extensive later-stage Phase 3 clinical trials, to demonstrate the safety and efficacy of our product candidates in humans. Clinical testing is expensive, difficult to design and implement, can take many years to complete and is uncertain as to outcome. A failure of one or more clinical trials can occur at any stage of testing. The outcome of preclinical testing and early clinical trials may not be predictive of the success of later clinical trials, and interim results of a clinical trial do not necessarily predict final results. The design of a clinical trial can determine whether its results will support approval of a product, and flaws in the design of a clinical trial may not become apparent until the clinical trial is well advanced or completed. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing approval of their products.

We have not completed any clinical trials of lefamulin specifically for CABP. Our completed Phase 2 clinical trial evaluated lefamulin in patients with acute bacterial skin and skin structure infections, or ABSSSI. Our Phase 1 clinical trials evaluated lefamulin in healthy subjects to obtain tolerance data and to understand the absorption and distribution of lefamulin in the blood and target tissues, evaluate the metabolism and elimination route of lefamulin and obtain safety and tolerability data to help predict safe and effective doses of lefamulin for the treatment of patients. In addition, we are using a different intravenous, or IV, formulation of lefamulin for our Phase 3 clinical trials for CABP than we used in our Phase 2 clinical trial for ABSSSI. We have only evaluated this new IV formulation of lefamulin, a sterile saline solution buffered by a citrate salt, in Phase 1 clinical trials. Because of these and other factors, the results of our completed clinical trials may not predict

success in our Phase 3 clinical trials of lefamulin for CABP. Although we believe that the collective data from prior trials and our preclinical studies provide support for concluding that lefamulin is well suited for treatment of CABP, we may fail to obtain favorable results in our Phase 3 clinical trials of lefamulin for CABP. If the results of our Phase 3 clinical trials are not favorable, including failure to achieve the primary efficacy endpoints of the trials, we may need to conduct additional clinical trials at significant cost or altogether abandon development of lefamulin for CABP and potentially other indications.

If we are required to conduct additional clinical trials or other testing of lefamulin or any other product candidate that we develop beyond those that we contemplate, if we are unable to successfully complete our clinical trials or other testing, if the results of these trials or tests are not positive or are only modestly positive or if there are safety concerns, we may:

·obtain approval for indications or patient populations that are not as broad as intended or desired;

·obtain approval with labeling that includes significant use or distribution restrictions or safety warnings, including boxed warnings;

·be subject to additional post-marketing testing requirements or restrictions; or

·have the product removed from the market after obtaining marketing approval.

The occurrence of any of the developments listed above could materially harm our business, financial condition, results of operations and prospects.

If we experience any of a number of possible unforeseen events in connection with our Phase 3 clinical trials of lefamulin for CABP or other clinical trials, the potential marketing approval or commercialization of lefamulin or other product candidates could be delayed or prevented.

We may experience numerous unforeseen events during, or as a result of, our Phase 3 clinical trials of lefamulin for CABP or other clinical trials we conduct that could delay or prevent our ability to receive marketing approval or commercialize lefamulin or our other product candidates, including:

·clinical trials of lefamulin or our other product candidates may produce negative or inconclusive results, and we may decide, or regulators may require us, to conduct additional clinical trials or abandon product development programs;

·the number of patients required for clinical trials of lefamulin for CABP, lefamulin for other indications or our other product candidates may be larger than we anticipate, enrollment in these clinical trials may be slower than we anticipate or participants may drop out of these clinical trials at a higher rate than we anticipate;

·we may be unable to enroll a sufficient number of patients in our Phase 3 clinical trials of lefamulin for CABP or other clinical trials we conduct to ensure adequate statistical power to detect any statistically significant treatment effects;

·our third-party contractors may fail to comply with regulatory requirements or meet their contractual obligations to us in a timely manner, or at all;

·regulators, institutional review boards or independent ethics committees may not authorize us or our investigators to commence a clinical trial or conduct a clinical trial at a prospective trial site or may require that we or our investigators suspend or terminate clinical research for various reasons, including noncompliance with regulatory requirements or a finding that the participants are being exposed to unacceptable health risks;

·we may have to suspend or terminate our Phase 3 clinical trials of lefamulin for CABP or other clinical trials of our product candidates for various reasons, including a finding that the participants are being exposed to unacceptable health risks;

·the cost of clinical trials of our product candidates may be greater than we anticipate;

·the supply or quality of our product candidates or other materials necessary to conduct clinical trials of our product candidates may be insufficient or inadequate; and

·our product candidates may have undesirable side effects or other unexpected characteristics, causing us or our investigators, regulators, institutional review boards or independent ethics committees to suspend or terminate the trials.

Our product development costs will increase if we experience delays in enrollment in our clinical development program or our non-clinical development program or in obtaining marketing approvals. We do not know whether any additional non-clinical tests or clinical trials will be required, or if they will begin as planned, or if they will need to be restructured or will be completed on schedule, or at all. Significant non-clinical development program delays, including chemistry, manufacturing and control activities, or clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize our product candidates or allow our competitors to bring products to market before we do and impair our ability to successfully commercialize our product candidates and may harm our business and results of operations.

If we experience delays or difficulties in the enrollment of patients in our clinical trials, our receipt of necessary marketing approvals could be delayed or prevented.

We may not be able to initiate or continue clinical trials of lefamulin or any other product candidate that we develop if we are unable to locate and enroll a sufficient number of eligible patients to participate in these clinical trials. In particular, we may experience enrollment challenges at trial sites in the United States, where it is a common practice to place patients with potential moderate to severe CABP on antibiotics very shortly after examination. This practice could prevent potential trial patients in the United States from being enrolled in our clinical trials based on our eligibility criteria. In addition, some of our competitors have ongoing clinical trials for product candidates that could be competitive with lefamulin, and patients who would otherwise be eligible for our clinical trials may instead enroll in clinical trials of our competitors product candidates.

Patient enrollment is affected by other factors including:

·severity of the disease under investigation;

·eligibility criteria for the clinical trial in question;

·perceived risks and benefits of the product candidate under study;

·approval of other therapies to treat the disease under investigation;

·efforts to facilitate timely enrollment in clinical trials;

·patient referral practices of physicians;

·the time of year in which the trial is initiated or conducted;

·the geographic distribution of global trial sites, given the timing of pneumonia season globally, and the seasonal variation in the number of patients suffering from pneumonia, including a decline in the number of patients with CABP during the summer months;

·the ability to monitor patients adequately during and after treatment;

·proximity and availability of clinical trial sites for prospective patients;

·delays in the receipt of required regulatory approvals, or the failure to receive required regulatory

approvals, in the jurisdictions in which clinical trials are expected to be conducted; and

·delays in the receipt of approvals, or the failure to receive approvals, from the relevant institutional review board or ethics committee at clinical trial sites.

For example, in each of our Phase 3 clinical trials of lefamulin, patients who have previously taken no more than one dose of a short acting, potentially effective antibiotic for the treatment of the current CABP episode within 24 hours of receiving the first dose of study medication will be allowed to participate in the trial but will comprise only up to 25% of the total intent to treat populations. Depending upon a regions or a clinical trial sites standard of care for the administration of antibiotics, this could affect our ability to enroll patients in these clinical trials in a timely fashion. Also, enrollment for our Phase 3 clinical trials may be negatively impacted by delays in opening clinical trial sites or the duration and/or severity of the influenza season. Moreover, our estimates regarding patient enrollment for our Phase 3 clinical trials of lefamulin depend on increasing enrollment rates as each such trial progresses, making it more difficult to precisely estimate the time of completion of such trials during its earlier stages. Enrollment delays in our clinical trials may result in increased development costs for our product candidates, which would cause the value of the company to decline and limit our ability to obtain additional financing. Our inability to enroll a sufficient number of patients in our Phase 3 clinical trials of lefamulin for CABP or any of our other clinical trials would result in significant delays or may require us to abandon one or more clinical trials altogether.

If serious adverse or undesirable side effects are identified during the development of lefamulin or any other product candidate that we develop, we may need to abandon or limit our development of that product candidate.

All of our product candidates are in clinical or preclinical development and their risk of failure is high. It is impossible to predict when or if any of our product candidates will prove effective or safe in humans or will receive marketing approval. If our product candidates are associated with undesirable side effects or have characteristics that are unexpected, we may need to abandon their development or limit development to certain uses or subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective. Many compounds that initially showed promise in clinical or earlier stage testing have later been found to cause side effects or other safety issues that prevented further development of the compound.

Lefamulin was well tolerated in our Phase 2 clinical trial for ABSSSI. No patient in the trial suffered any serious adverse events that were found to be related to lefamulin, and no patient in the trial died. Some patients experienced adverse events that were assessed by the investigator as possibly or probably related to study medication. The majority of their symptoms were mild in severity. Four patients discontinued study medication following a drug-related event, three of whom were in a lefamulin treatment group: one patient experienced events of hyperhidrosis, vomiting and headache; one patient experienced infusion site pain; and one patient experienced dyspnea.

Because the potential for mild effect on electrocardiogram, or ECG, measurements was observed in preclinical studies, we have continued to assess this potential in all human clinical trials we have conducted. In the Phase 2 clinical trial, no change in ECG measurements was considered to be of clinical significance, and no drug-related cardiovascular adverse event was reported. Both lefamulin and vancomycin treatment were associated with a small increase in the QT interval. The QT interval is a measure of the hearts electrical cycle, with a lengthened QT interval representing a marker for potential ventricular arrhythmia. We are continuing to evaluate the effect of lefamulin on the QT interval in our Phase 3 clinical trials of lefamulin for CABP.

There were no systemic adverse events of clinical concern and no drug-related serious adverse events observed in any of our completed Phase 1 clinical trials of lefamulin. In these trials, the most commonly observed adverse effects with oral administration of lefamulin were related to the gastrointestinal tract, including nausea and abdominal discomfort, while the most commonly observed adverse effects related to IV administration were related to irritation at the infusion site. In addition, lefamulin produced a transient, predictable and reproducible prolongation of the QT interval based on the maximum concentration of the drug in the blood plasma. At therapeutic doses, we expect that the drug will not produce large effects on the QT interval that would be of clinical relevance. We did not observe any drug-related cardiac adverse events, such as increase in ectopic ventricular activity or other cardiac arrhythmia, or clinically relevant ECG findings during the conduct of any of our completed Phase 1 clinical trials. None of the ECG stopping criteria defined in the trial protocols was reached in any clinical trial. However, if we observe clinically relevant effects on the QT interval

in our Phase 3 clinical trials of lefamulin for CABP or in any other clinical trial of lefamulin, our ability to successfully develop lefamulin for CABP or any other indication may be significantly delayed or prevented.

If we elect or are forced to suspend or terminate any clinical trial of lefamulin or any other product candidates that we are developing, the commercial prospects of lefamulin or such other product candidates will be harmed and our ability to generate product revenues, if at all, from lefamulin or any of these other product candidates will be delayed or eliminated. Any of these occurrences could materially harm our business, financial condition, results of operations and prospects.

Even if lefamulin or any other product candidate receives marketing approval, it may fail to achieve the degree of market acceptance by physicians, patients, third-party payors and others in the medical community necessary for commercial success and the market opportunity for lefamulin may be smaller than we estimate.

If lefamulin or any of our other product candidates receive marketing approval, they may nonetheless fail to gain sufficient market acceptance by physicians, patients, third-party payors and others in the medical community. For example, current treatments for pneumonia, including generic options, are well established in the medical community, and doctors may continue to rely on these treatments without lefamulin. In addition, our efforts to effectively communicate lefamulins differentiating characteristics and key attributes to clinicians and hospital pharmacies with the goal of establishing favorable formulary status for lefamulin may fail or may be less successful than we expect. If lefamulin does not achieve an adequate level of acceptance, we may not generate significant product revenues or any profits from operations. The degree of market acceptance of our product candidates, if approved for commercial sale, will depend on a number of factors, including: